#pragma GCC optimize ("Ofast")
#include<bits/stdc++.h>
using namespace std;
template<class S, class T> inline S max_L(S a,T b){
  return a>=b?a:b;
}
struct Rand{
  unsigned x;
  unsigned y;
  unsigned z;
  unsigned w;
  Rand(void){
    x=123456789;
    y=362436069;
    z=521288629;
    w=(unsigned)time(NULL);
  }
  Rand(unsigned seed){
    x=123456789;
    y=362436069;
    z=521288629;
    w=seed;
  }
  inline unsigned get(void){
    unsigned t;
    t = (x^(x<<11));
    x=y;
    y=z;
    z=w;
    w = (w^(w>>19))^(t^(t>>8));
    return w;
  }
  inline double getUni(void){
    return get()/4294967296.0;
  }
  inline int get(int a){
    return (int)(a*getUni());
  }
  inline int get(int a, int b){
    return a+(int)((b-a+1)*getUni());
  }
  inline long long get(long long a){
    return(long long)(a*getUni());
  }
  inline long long get(long long a, long long b){
    return a+(long long)((b-a+1)*getUni());
  }
  inline double get(double a, double b){
    return a+(b-a)*getUni();
  }
  inline int getExp(int a){
    return(int)(exp(getUni()*log(a+1.0))-1.0);
  }
  inline int getExp(int a, int b){
    return a+(int)(exp(getUni()*log((b-a+1)+1.0))-1.0);
  }
}
;
inline int my_getchar(){
  static char buf[1048576];
  static int s = 1048576;
  static int e = 1048576;
  if(s == e && e == 1048576){
    e = fread(buf, 1, 1048576, stdin);
    s = 0;
  }
  if(s == e){
    return EOF;
  }
  return buf[s++];
}
inline void rd(int &x){
  int k;
  int m=0;
  x=0;
  for(;;){
    k = my_getchar();
    if(k=='-'){
      m=1;
      break;
    }
    if('0'<=k&&k<='9'){
      x=k-'0';
      break;
    }
  }
  for(;;){
    k = my_getchar();
    if(k<'0'||k>'9'){
      break;
    }
    x=x*10+k-'0';
  }
  if(m){
    x=-x;
  }
}
inline void rd(char &c){
  int i;
  for(;;){
    i = my_getchar();
    if(i!=' '&&i!='\n'&&i!='\r'&&i!='\t'&&i!=EOF){
      break;
    }
  }
  c = i;
}
inline int rd(char c[]){
  int i;
  int sz = 0;
  for(;;){
    i = my_getchar();
    if(i!=' '&&i!='\n'&&i!='\r'&&i!='\t'&&i!=EOF){
      break;
    }
  }
  c[sz++] = i;
  for(;;){
    i = my_getchar();
    if(i==' '||i=='\n'||i=='\r'||i=='\t'||i==EOF){
      break;
    }
    c[sz++] = i;
  }
  c[sz]='\0';
  return sz;
}
inline int rd_int(void){
  int x;
  rd(x);
  return x;
}
struct MY_WRITER{
  char buf[1048576];
  int s;
  int e;
  MY_WRITER(){
    s = 0;
    e = 1048576;
  }
  ~MY_WRITER(){
    if(s){
      fwrite(buf, 1, s, stdout);
    }
  }
}
;
MY_WRITER MY_WRITER_VAR;
void my_putchar(int a){
  if(MY_WRITER_VAR.s == MY_WRITER_VAR.e){
    fwrite(MY_WRITER_VAR.buf, 1, MY_WRITER_VAR.s, stdout);
    MY_WRITER_VAR.s = 0;
  }
  MY_WRITER_VAR.buf[MY_WRITER_VAR.s++] = a;
}
inline void wt_L(char a){
  my_putchar(a);
}
inline void wt_L(const char c[]){
  int i=0;
  for(i=0;c[i]!='\0';i++){
    my_putchar(c[i]);
  }
}
template<class T, class U> inline T GCD_L(T a, U b){
  T r;
  while(b){
    r=a;
    a=b;
    b=r%a;
  }
  return a;
}
#define ROLLING_HASH_MOD (2305843009213693951ULL)
#define ROLLING_HASH_PRIMITIVE_ROOT (3)
#define ROLLING_HASH_MAX_MEMORY (2000000)
int ROLLING_HASH_MEM;
unsigned long long ROLLING_HASH_BASE;
unsigned long long ROLLING_HASH_IBASE;
unsigned long long*ROLLING_HASH_PW = NULL;
unsigned long long*ROLLING_HASH_IPW = NULL;
inline unsigned long long rollingHash61_mul(unsigned long long a, unsigned long long b){
  __uint128_t r = (__uint128_t) a * b;
  a = (r >> 61) + (r & ROLLING_HASH_MOD);
  if(a >= ROLLING_HASH_MOD){
    a -= ROLLING_HASH_MOD;
  }
  return a;
}
inline unsigned long long rollingHash61_pow(unsigned long long a, unsigned long long b){
  unsigned long long r = 1;
  for(;;){
    if(b&1){
      r = rollingHash61_mul(r, a);
    }
    if(b==0){
      break;
    }
    b >>= 1;
    a = rollingHash61_mul(a, a);
  }
  return r;
}
void rollingHashInit(){
  int i;
  Rand rnd;
  unsigned long long x;
  for(i=(0);i<(20);i++){
    rnd.get(2);
  }
  do{
    x = rnd.get(1.0, (double)(ROLLING_HASH_MOD-2));
  }
  while(GCD_L(x, ROLLING_HASH_MOD-1)!= 1);
  ROLLING_HASH_BASE = rollingHash61_pow(ROLLING_HASH_PRIMITIVE_ROOT, x);
  ROLLING_HASH_IBASE = rollingHash61_pow(ROLLING_HASH_BASE, ROLLING_HASH_MOD - 2);
}
void rollingHash_expand(int k){
  int i;
  if(ROLLING_HASH_MEM >= k){
    return;
  }
  ROLLING_HASH_MEM =max_L(2 * ROLLING_HASH_MEM, k);
  assert(ROLLING_HASH_MEM <= 2 * ROLLING_HASH_MAX_MEMORY);
  ROLLING_HASH_PW = (unsigned long long*) realloc(ROLLING_HASH_PW, ROLLING_HASH_MEM * sizeof(unsigned long long));
  ROLLING_HASH_IPW = (unsigned long long*) realloc(ROLLING_HASH_IPW, ROLLING_HASH_MEM * sizeof(unsigned long long));
  ROLLING_HASH_PW[0] = 1;
  for(i=(1);i<(ROLLING_HASH_MEM);i++){
    ROLLING_HASH_PW[i] = rollingHash61_mul(ROLLING_HASH_PW[i-1], ROLLING_HASH_BASE);
  }
  ROLLING_HASH_IPW[0] = 1;
  for(i=(1);i<(ROLLING_HASH_MEM);i++){
    ROLLING_HASH_IPW[i] = rollingHash61_mul(ROLLING_HASH_IPW[i-1], ROLLING_HASH_IBASE);
  }
}
struct rollingHash{
  long long len;
  unsigned long long hs;
  template<class T> void set(int N, T A[]){
    int i;
    long long tmp;
    hs = 0;
    len = N;
    rollingHash_expand(N);
    for(i=(0);i<(N);i++){
      tmp = A[i] % ((long long)ROLLING_HASH_MOD);
      if(tmp < 0){
        tmp += ROLLING_HASH_MOD;
      }
      hs += rollingHash61_mul(tmp, ROLLING_HASH_PW[i]);
      if(hs >= ROLLING_HASH_MOD){
        hs -= ROLLING_HASH_MOD;
      }
    }
  }
  template<class S, class T> void change(long long ind, S bef, T aft){
    long long tmp1;
    long long tmp2;
    tmp1 = bef % ((long long)ROLLING_HASH_MOD);
    tmp2 = aft % ((long long)ROLLING_HASH_MOD);
    tmp1 = tmp2 - tmp1;
    if(tmp1 < 0){
      tmp1 += ROLLING_HASH_MOD;
    }
    if(tmp1 < 0){
      tmp1 += ROLLING_HASH_MOD;
    }
    if(tmp1 >= ROLLING_HASH_MOD){
      tmp1 -= ROLLING_HASH_MOD;
    }
    if(ind+1 <= ROLLING_HASH_MAX_MEMORY || ind+1 >= ROLLING_HASH_MEM){
      rollingHash_expand(ind+1);
      hs += rollingHash61_mul(tmp1, ROLLING_HASH_PW[ind]);
    }
    else{
      hs += rollingHash61_mul(tmp1, rollingHash61_pow(ROLLING_HASH_BASE, ind));
    }
    if(hs >= ROLLING_HASH_MOD){
      hs -= ROLLING_HASH_MOD;
    }
  }
  void push_front(rollingHash a){
    if(a.len + 1 <= ROLLING_HASH_MAX_MEMORY || a.len + 1 >= ROLLING_HASH_MEM){
      rollingHash_expand(a.len + 1);
      hs = rollingHash61_mul(hs, ROLLING_HASH_PW[a.len]);
    }
    else{
      hs = rollingHash61_mul(hs, rollingHash61_pow(ROLLING_HASH_BASE, a.len));
    }
    hs += a.hs;
    if(hs >= ROLLING_HASH_MOD){
      hs -= ROLLING_HASH_MOD;
    }
    len += a.len;
  }
  void push_back(rollingHash a){
    if(len + 1 <= ROLLING_HASH_MAX_MEMORY || len + 1 >= ROLLING_HASH_MEM){
      rollingHash_expand(len + 1);
      hs += rollingHash61_mul(a.hs, ROLLING_HASH_PW[len]);
    }
    else{
      hs += rollingHash61_mul(a.hs, rollingHash61_pow(ROLLING_HASH_BASE, len));
    }
    if(hs >= ROLLING_HASH_MOD){
      hs -= ROLLING_HASH_MOD;
    }
    len += a.len;
  }
  void pop_front(rollingHash a){
    if(hs >= a.hs){
      hs -= a.hs;
    }
    else{
      hs = hs + ROLLING_HASH_MOD - a.hs;
    }
    if(a.len + 1 <= ROLLING_HASH_MAX_MEMORY || a.len + 1 >= ROLLING_HASH_MEM){
      rollingHash_expand(a.len + 1);
      hs = rollingHash61_mul(hs, ROLLING_HASH_IPW[a.len]);
    }
    else{
      hs = rollingHash61_mul(hs, rollingHash61_pow(ROLLING_HASH_IBASE, a.len));
    }
    len -= a.len;
  }
  void pop_back(rollingHash a){
    unsigned long long tmp;
    if(len + 1 <= ROLLING_HASH_MAX_MEMORY || len + 1 >= ROLLING_HASH_MEM){
      rollingHash_expand(len + 1);
      tmp = rollingHash61_mul(a.hs, ROLLING_HASH_PW[len]);
    }
    else{
      tmp = rollingHash61_mul(a.hs, rollingHash61_pow(ROLLING_HASH_BASE, len));
    }
    if(hs >= tmp){
      hs -= tmp;
    }
    else{
      hs = hs + ROLLING_HASH_MOD - tmp;
    }
    len -= a.len;
  }
  bool operator==(const rollingHash a){
    return len == a.len && hs == a.hs;
  }
  bool operator!=(const rollingHash a){
    return len != a.len || hs != a.hs;
  }
}
;
template<class T> rollingHash calcRollingHash(int N, T A[]){
  rollingHash res;
  res.set(N, A);
  return res;
}
struct rollingHashSubarrays{
  unsigned long long*hs;
  int mem;
  int len;
  void set(){
    hs = NULL;
    mem = len = 0;
  }
  void free(){
    if(mem){
      delete[] hs;
    }
  }
  void expand(int k){
    if(mem >= k){
      return;
    }
    free();
    mem =max_L(2*mem, k);
    hs = new unsigned long long[mem];
  }
  template<class T> void set(int N, T A[]){
    int i;
    long long tmp;
    if(N <= 0){
      return;
    }
    rollingHash_expand(N);
    expand(N);
    len = N;
    tmp = A[0] % ((long long)ROLLING_HASH_MOD);
    if(tmp < 0){
      tmp += ROLLING_HASH_MOD;
    }
    hs[0] = tmp;
    for(i=(1);i<(N);i++){
      tmp = A[i] % ((long long)ROLLING_HASH_MOD);
      if(tmp < 0){
        tmp += ROLLING_HASH_MOD;
      }
      hs[i] = hs[i-1] + rollingHash61_mul(tmp, ROLLING_HASH_PW[i]);
      if(hs[i] >= ROLLING_HASH_MOD){
        hs[i] -= ROLLING_HASH_MOD;
      }
    }
  }
  rollingHash get_len(int s, int len){
    unsigned long long x;
    rollingHash res;
    res.len = len;
    rollingHash_expand(s+1);
    if(s == 0){
      res.hs = hs[len-1];
    }
    else{
      if(hs[s+len-1] >= hs[s-1]){
        res.hs = hs[s+len-1] - hs[s-1];
      }
      else{
        res.hs = hs[s+len-1] + ROLLING_HASH_MOD - hs[s-1];
      }
      res.hs = rollingHash61_mul(res.hs, ROLLING_HASH_IPW[s]);
    }
    return res;
  }
  rollingHash get(int a, int b){
    return get_len(a, b - a + 1);
  }
  rollingHashSubarrays(){
    set();
  }
  ~rollingHashSubarrays(){
    free();
  }
}
;
unsigned long long HashMap_ullP_L[4];
template<class KEY, class VAL> struct HashMap{
  char*used;
  KEY*key;
  VAL*val;
  int mem;
  int n;
  int mask;
  HashMap(){
    mem = 0;
  }
  ~HashMap(){
    free();
  }
  void expand(int nn){
    if(mem >= nn){
      return;
    }
    if(mem){
      free();
    }
    mem = nn;
    used = new char[nn];
    key = new KEY[nn];
    val = new VAL[nn];
  }
  void free(){
    if(mem){
      mem = 0;
      delete[] used;
      delete[] key;
      delete[] val;
    }
  }
  void init(int nn){
    int i;
    n = 1;
    nn = nn + (nn + 1) / 2;
    while(n < nn){
      n *= 2;
    }
    mask = n - 1;
    expand(n);
    for(i=(0);i<(n);i++){
      used[i] = 0;
    }
  }
  inline int getHash(const int a){
    unsigned long long d = a;
    d = (((d * HashMap_ullP_L[0]) >> 32) * HashMap_ullP_L[1]) & mask;
    return d;
  }
  inline int getHash(const unsigned a){
    unsigned long long d = a;
    d = (((d * HashMap_ullP_L[0]) >> 32) * HashMap_ullP_L[1]) & mask;
    return d;
  }
  inline int getHash(const long long a){
    unsigned long long d = a;
    d = (((((d * HashMap_ullP_L[0]) >> 32) * HashMap_ullP_L[1]) >> 32) * HashMap_ullP_L[2]) & mask;
    return d;
  }
  inline int getHash(const unsigned long long a){
    unsigned long long d = a;
    d = (((((d * HashMap_ullP_L[0]) >> 32) * HashMap_ullP_L[1]) >> 32) * HashMap_ullP_L[2]) & mask;
    return d;
  }
  inline int getHash(const pair<int,int> a){
    unsigned long long d = (((unsigned long long)a.first) << 32) + ((unsigned long long)a.second);
    d = (((((d * HashMap_ullP_L[0]) >> 32) * HashMap_ullP_L[1]) >> 32) * HashMap_ullP_L[2]) & mask;
    return d;
  }
  inline VAL& operator[](const KEY a){
    int k = getHash(a);
    for(;;){
      if(used[k]==1 && key[k]==a){
        break;
      }
      if(used[k]==0){
        used[k] = 1;
        key[k] = a;
        break;
      }
      k = (k+1) & mask;
    }
    return val[k];
  }
  inline bool exist(const KEY a){
    int k = getHash(a);
    for(;;){
      if(used[k]==1 && key[k]==a){
        return true;
      }
      if(used[k]==0){
        break;
      }
      k = (k+1) & mask;
    }
    return false;
  }
  template<class S> inline bool exist(const KEY a, S &res){
    int k = getHash(a);
    for(;;){
      if(used[k]==1 && key[k]==a){
        res = val[k];
        return true;
      }
      if(used[k]==0){
        break;
      }
      k = (k+1) & mask;
    }
    return false;
  }
}
;
int N;
int K;
char S[1000000+2];
char res[1000000+2];
int main(){
  int Lj4PdHRW;
  {
    rollingHashInit();
  }
  {
    int i;
    int j;
    int k;
    Rand rnd;
    for(i=(0);i<(20);i++){
      rnd.get(2);
    }
    for(i=(0);i<(4);i++){
      for(j=(0);j<(32);j++){
        k = rnd.get(1,62);
        HashMap_ullP_L[i] |= (1ULL << k);
      }
      HashMap_ullP_L[i] |= (1ULL << 0);
      HashMap_ullP_L[i] |= (1ULL << 63);
    }
  }
  HashMap<unsigned long long,int> mp;
  rollingHash h;
  rollingHashSubarrays arr;
  int KL2GvlyY = rd_int();
  for(Lj4PdHRW=(0);Lj4PdHRW<(KL2GvlyY);Lj4PdHRW++){
    int i;
    rd(N);
    rd(K);
    rd(S);
    for(i=(0);i<(N);i++){
      S[i] = (S[i] - '0') ^ 1;
    }
    arr.set(N, S);
    mp.init(N-K+1);
    for(i=(0);i<(N-K+1);i++){
      mp[arr.get_len(i,K).hs] = 1;
    }
    for(i=(0);i<(K);i++){
      res[i] = 0;
    }
    h = calcRollingHash(K, res);
    for(;;){
      int j;
      if(!mp.exist(h.hs)){
        wt_L("YES");
        wt_L('\n');
        for(i=(0);i<(K);i++){
          res[i] += '0';
        }
        res[K] = '\0';
        wt_L(res);
        wt_L('\n');
        break;
      }
      for(i=(K)-1;i>=(0);i--){
        if(res[i] == 0){
          break;
        }
      }
      if(i==-1){
        wt_L("NO");
        wt_L('\n');
        break;
      }
      res[i] = 1;
      h.change(i, 0, 1);
      for(j=(i+1);j<(K);j++){
        res[j] = 0;
        h.change(j, 1, 0);
      }
    }
  }
  return 0;
}
// cLay version 20201229-1

// --- original code ---
// //no-unlocked
// int N, K; char S[1d6+2], res[1d6+2];
// {
//   HashMap<ull,int> mp;
//   rollingHash h;
//   rollingHashSubarrays arr;
//   REP(rd_int()){
//     rd(N,K,S);
//     rep(i,N) S[i] = (S[i] - '0') ^ 1;
// 
//     arr.set(N, S);
//     mp.init(N-K+1);
//     rep(i,N-K+1) mp[arr.get_len(i,K).hs] = 1;
// 
//     rep(i,K) res[i] = 0;
//     h = calcRollingHash(K, res);
//     for(;;){
//       if(!mp.exist(h.hs)){
//         wt("YES");
//         rep(i,K) res[i] += '0';
//         res[K] = '\0';
//         wt(res);
//         break;
//       }
// 
//       rrep(i,K) if(res[i] == 0) break;
//       if(i==-1) wt("NO"), break;
//       res[i] = 1; h.change(i, 0, 1);
//       rep(j,i+1,K) res[j] = 0, h.change(j, 1, 0);
//     }
//   }
// }

### Prompt

Create a solution in CPP for the following problem:

Let's call two strings a and b (both of length k) a bit similar if they have the same character in some position, i. e. there exists at least one i ∈ [1, k] such that a_i = b_i.

You are given a binary string s of length n (a string of n characters 0 and/or 1) and an integer k. Let's denote the string s[i..j] as the substring of s starting from the i-th character and ending with the j-th character (that is, s[i..j] = s_i s_{i + 1} s_{i + 2} ... s_{j - 1} s_j).

Let's call a binary string t of length k beautiful if it is a bit similar to all substrings of s having length exactly k; that is, it is a bit similar to s[1..k], s[2..k+1], ..., s[n-k+1..n].

Your goal is to find the lexicographically smallest string t that is beautiful, or report that no such string exists. String x is lexicographically less than string y if either x is a prefix of y (and x ≠ y), or there exists such i (1 ≤ i ≤ min(|x|, |y|)), that x_i < y_i, and for any j (1 ≤ j < i) x_j = y_j.

Input

The first line contains one integer q (1 ≤ q ≤ 10000) — the number of test cases. Each test case consists of two lines.

The first line of each test case contains two integers n and k (1 ≤ k ≤ n ≤ 10^6). The second line contains the string s, consisting of n characters (each character is either 0 or 1).

It is guaranteed that the sum of n over all test cases does not exceed 10^6.

Output

For each test case, print the answer as follows:

  * if it is impossible to construct a beautiful string, print one line containing the string NO (note: exactly in upper case, you can't print No, for example); 
  * otherwise, print two lines. The first line should contain the string YES (exactly in upper case as well); the second line — the lexicographically smallest beautiful string, consisting of k characters 0 and/or 1. 

Example

Input


7
4 2
0110
4 2
1001
9 3
010001110
9 3
101110001
10 3
0101110001
10 10
1111111111
11 10
11111111110


Output


YES
11
YES
00
YES
010
YES
101
NO
YES
0000000001
YES
0000000010

### Response

```cpp
#pragma GCC optimize ("Ofast")
#include<bits/stdc++.h>
using namespace std;
template<class S, class T> inline S max_L(S a,T b){
  return a>=b?a:b;
}
struct Rand{
  unsigned x;
  unsigned y;
  unsigned z;
  unsigned w;
  Rand(void){
    x=123456789;
    y=362436069;
    z=521288629;
    w=(unsigned)time(NULL);
  }
  Rand(unsigned seed){
    x=123456789;
    y=362436069;
    z=521288629;
    w=seed;
  }
  inline unsigned get(void){
    unsigned t;
    t = (x^(x<<11));
    x=y;
    y=z;
    z=w;
    w = (w^(w>>19))^(t^(t>>8));
    return w;
  }
  inline double getUni(void){
    return get()/4294967296.0;
  }
  inline int get(int a){
    return (int)(a*getUni());
  }
  inline int get(int a, int b){
    return a+(int)((b-a+1)*getUni());
  }
  inline long long get(long long a){
    return(long long)(a*getUni());
  }
  inline long long get(long long a, long long b){
    return a+(long long)((b-a+1)*getUni());
  }
  inline double get(double a, double b){
    return a+(b-a)*getUni();
  }
  inline int getExp(int a){
    return(int)(exp(getUni()*log(a+1.0))-1.0);
  }
  inline int getExp(int a, int b){
    return a+(int)(exp(getUni()*log((b-a+1)+1.0))-1.0);
  }
}
;
inline int my_getchar(){
  static char buf[1048576];
  static int s = 1048576;
  static int e = 1048576;
  if(s == e && e == 1048576){
    e = fread(buf, 1, 1048576, stdin);
    s = 0;
  }
  if(s == e){
    return EOF;
  }
  return buf[s++];
}
inline void rd(int &x){
  int k;
  int m=0;
  x=0;
  for(;;){
    k = my_getchar();
    if(k=='-'){
      m=1;
      break;
    }
    if('0'<=k&&k<='9'){
      x=k-'0';
      break;
    }
  }
  for(;;){
    k = my_getchar();
    if(k<'0'||k>'9'){
      break;
    }
    x=x*10+k-'0';
  }
  if(m){
    x=-x;
  }
}
inline void rd(char &c){
  int i;
  for(;;){
    i = my_getchar();
    if(i!=' '&&i!='\n'&&i!='\r'&&i!='\t'&&i!=EOF){
      break;
    }
  }
  c = i;
}
inline int rd(char c[]){
  int i;
  int sz = 0;
  for(;;){
    i = my_getchar();
    if(i!=' '&&i!='\n'&&i!='\r'&&i!='\t'&&i!=EOF){
      break;
    }
  }
  c[sz++] = i;
  for(;;){
    i = my_getchar();
    if(i==' '||i=='\n'||i=='\r'||i=='\t'||i==EOF){
      break;
    }
    c[sz++] = i;
  }
  c[sz]='\0';
  return sz;
}
inline int rd_int(void){
  int x;
  rd(x);
  return x;
}
struct MY_WRITER{
  char buf[1048576];
  int s;
  int e;
  MY_WRITER(){
    s = 0;
    e = 1048576;
  }
  ~MY_WRITER(){
    if(s){
      fwrite(buf, 1, s, stdout);
    }
  }
}
;
MY_WRITER MY_WRITER_VAR;
void my_putchar(int a){
  if(MY_WRITER_VAR.s == MY_WRITER_VAR.e){
    fwrite(MY_WRITER_VAR.buf, 1, MY_WRITER_VAR.s, stdout);
    MY_WRITER_VAR.s = 0;
  }
  MY_WRITER_VAR.buf[MY_WRITER_VAR.s++] = a;
}
inline void wt_L(char a){
  my_putchar(a);
}
inline void wt_L(const char c[]){
  int i=0;
  for(i=0;c[i]!='\0';i++){
    my_putchar(c[i]);
  }
}
template<class T, class U> inline T GCD_L(T a, U b){
  T r;
  while(b){
    r=a;
    a=b;
    b=r%a;
  }
  return a;
}
#define ROLLING_HASH_MOD (2305843009213693951ULL)
#define ROLLING_HASH_PRIMITIVE_ROOT (3)
#define ROLLING_HASH_MAX_MEMORY (2000000)
int ROLLING_HASH_MEM;
unsigned long long ROLLING_HASH_BASE;
unsigned long long ROLLING_HASH_IBASE;
unsigned long long*ROLLING_HASH_PW = NULL;
unsigned long long*ROLLING_HASH_IPW = NULL;
inline unsigned long long rollingHash61_mul(unsigned long long a, unsigned long long b){
  __uint128_t r = (__uint128_t) a * b;
  a = (r >> 61) + (r & ROLLING_HASH_MOD);
  if(a >= ROLLING_HASH_MOD){
    a -= ROLLING_HASH_MOD;
  }
  return a;
}
inline unsigned long long rollingHash61_pow(unsigned long long a, unsigned long long b){
  unsigned long long r = 1;
  for(;;){
    if(b&1){
      r = rollingHash61_mul(r, a);
    }
    if(b==0){
      break;
    }
    b >>= 1;
    a = rollingHash61_mul(a, a);
  }
  return r;
}
void rollingHashInit(){
  int i;
  Rand rnd;
  unsigned long long x;
  for(i=(0);i<(20);i++){
    rnd.get(2);
  }
  do{
    x = rnd.get(1.0, (double)(ROLLING_HASH_MOD-2));
  }
  while(GCD_L(x, ROLLING_HASH_MOD-1)!= 1);
  ROLLING_HASH_BASE = rollingHash61_pow(ROLLING_HASH_PRIMITIVE_ROOT, x);
  ROLLING_HASH_IBASE = rollingHash61_pow(ROLLING_HASH_BASE, ROLLING_HASH_MOD - 2);
}
void rollingHash_expand(int k){
  int i;
  if(ROLLING_HASH_MEM >= k){
    return;
  }
  ROLLING_HASH_MEM =max_L(2 * ROLLING_HASH_MEM, k);
  assert(ROLLING_HASH_MEM <= 2 * ROLLING_HASH_MAX_MEMORY);
  ROLLING_HASH_PW = (unsigned long long*) realloc(ROLLING_HASH_PW, ROLLING_HASH_MEM * sizeof(unsigned long long));
  ROLLING_HASH_IPW = (unsigned long long*) realloc(ROLLING_HASH_IPW, ROLLING_HASH_MEM * sizeof(unsigned long long));
  ROLLING_HASH_PW[0] = 1;
  for(i=(1);i<(ROLLING_HASH_MEM);i++){
    ROLLING_HASH_PW[i] = rollingHash61_mul(ROLLING_HASH_PW[i-1], ROLLING_HASH_BASE);
  }
  ROLLING_HASH_IPW[0] = 1;
  for(i=(1);i<(ROLLING_HASH_MEM);i++){
    ROLLING_HASH_IPW[i] = rollingHash61_mul(ROLLING_HASH_IPW[i-1], ROLLING_HASH_IBASE);
  }
}
struct rollingHash{
  long long len;
  unsigned long long hs;
  template<class T> void set(int N, T A[]){
    int i;
    long long tmp;
    hs = 0;
    len = N;
    rollingHash_expand(N);
    for(i=(0);i<(N);i++){
      tmp = A[i] % ((long long)ROLLING_HASH_MOD);
      if(tmp < 0){
        tmp += ROLLING_HASH_MOD;
      }
      hs += rollingHash61_mul(tmp, ROLLING_HASH_PW[i]);
      if(hs >= ROLLING_HASH_MOD){
        hs -= ROLLING_HASH_MOD;
      }
    }
  }
  template<class S, class T> void change(long long ind, S bef, T aft){
    long long tmp1;
    long long tmp2;
    tmp1 = bef % ((long long)ROLLING_HASH_MOD);
    tmp2 = aft % ((long long)ROLLING_HASH_MOD);
    tmp1 = tmp2 - tmp1;
    if(tmp1 < 0){
      tmp1 += ROLLING_HASH_MOD;
    }
    if(tmp1 < 0){
      tmp1 += ROLLING_HASH_MOD;
    }
    if(tmp1 >= ROLLING_HASH_MOD){
      tmp1 -= ROLLING_HASH_MOD;
    }
    if(ind+1 <= ROLLING_HASH_MAX_MEMORY || ind+1 >= ROLLING_HASH_MEM){
      rollingHash_expand(ind+1);
      hs += rollingHash61_mul(tmp1, ROLLING_HASH_PW[ind]);
    }
    else{
      hs += rollingHash61_mul(tmp1, rollingHash61_pow(ROLLING_HASH_BASE, ind));
    }
    if(hs >= ROLLING_HASH_MOD){
      hs -= ROLLING_HASH_MOD;
    }
  }
  void push_front(rollingHash a){
    if(a.len + 1 <= ROLLING_HASH_MAX_MEMORY || a.len + 1 >= ROLLING_HASH_MEM){
      rollingHash_expand(a.len + 1);
      hs = rollingHash61_mul(hs, ROLLING_HASH_PW[a.len]);
    }
    else{
      hs = rollingHash61_mul(hs, rollingHash61_pow(ROLLING_HASH_BASE, a.len));
    }
    hs += a.hs;
    if(hs >= ROLLING_HASH_MOD){
      hs -= ROLLING_HASH_MOD;
    }
    len += a.len;
  }
  void push_back(rollingHash a){
    if(len + 1 <= ROLLING_HASH_MAX_MEMORY || len + 1 >= ROLLING_HASH_MEM){
      rollingHash_expand(len + 1);
      hs += rollingHash61_mul(a.hs, ROLLING_HASH_PW[len]);
    }
    else{
      hs += rollingHash61_mul(a.hs, rollingHash61_pow(ROLLING_HASH_BASE, len));
    }
    if(hs >= ROLLING_HASH_MOD){
      hs -= ROLLING_HASH_MOD;
    }
    len += a.len;
  }
  void pop_front(rollingHash a){
    if(hs >= a.hs){
      hs -= a.hs;
    }
    else{
      hs = hs + ROLLING_HASH_MOD - a.hs;
    }
    if(a.len + 1 <= ROLLING_HASH_MAX_MEMORY || a.len + 1 >= ROLLING_HASH_MEM){
      rollingHash_expand(a.len + 1);
      hs = rollingHash61_mul(hs, ROLLING_HASH_IPW[a.len]);
    }
    else{
      hs = rollingHash61_mul(hs, rollingHash61_pow(ROLLING_HASH_IBASE, a.len));
    }
    len -= a.len;
  }
  void pop_back(rollingHash a){
    unsigned long long tmp;
    if(len + 1 <= ROLLING_HASH_MAX_MEMORY || len + 1 >= ROLLING_HASH_MEM){
      rollingHash_expand(len + 1);
      tmp = rollingHash61_mul(a.hs, ROLLING_HASH_PW[len]);
    }
    else{
      tmp = rollingHash61_mul(a.hs, rollingHash61_pow(ROLLING_HASH_BASE, len));
    }
    if(hs >= tmp){
      hs -= tmp;
    }
    else{
      hs = hs + ROLLING_HASH_MOD - tmp;
    }
    len -= a.len;
  }
  bool operator==(const rollingHash a){
    return len == a.len && hs == a.hs;
  }
  bool operator!=(const rollingHash a){
    return len != a.len || hs != a.hs;
  }
}
;
template<class T> rollingHash calcRollingHash(int N, T A[]){
  rollingHash res;
  res.set(N, A);
  return res;
}
struct rollingHashSubarrays{
  unsigned long long*hs;
  int mem;
  int len;
  void set(){
    hs = NULL;
    mem = len = 0;
  }
  void free(){
    if(mem){
      delete[] hs;
    }
  }
  void expand(int k){
    if(mem >= k){
      return;
    }
    free();
    mem =max_L(2*mem, k);
    hs = new unsigned long long[mem];
  }
  template<class T> void set(int N, T A[]){
    int i;
    long long tmp;
    if(N <= 0){
      return;
    }
    rollingHash_expand(N);
    expand(N);
    len = N;
    tmp = A[0] % ((long long)ROLLING_HASH_MOD);
    if(tmp < 0){
      tmp += ROLLING_HASH_MOD;
    }
    hs[0] = tmp;
    for(i=(1);i<(N);i++){
      tmp = A[i] % ((long long)ROLLING_HASH_MOD);
      if(tmp < 0){
        tmp += ROLLING_HASH_MOD;
      }
      hs[i] = hs[i-1] + rollingHash61_mul(tmp, ROLLING_HASH_PW[i]);
      if(hs[i] >= ROLLING_HASH_MOD){
        hs[i] -= ROLLING_HASH_MOD;
      }
    }
  }
  rollingHash get_len(int s, int len){
    unsigned long long x;
    rollingHash res;
    res.len = len;
    rollingHash_expand(s+1);
    if(s == 0){
      res.hs = hs[len-1];
    }
    else{
      if(hs[s+len-1] >= hs[s-1]){
        res.hs = hs[s+len-1] - hs[s-1];
      }
      else{
        res.hs = hs[s+len-1] + ROLLING_HASH_MOD - hs[s-1];
      }
      res.hs = rollingHash61_mul(res.hs, ROLLING_HASH_IPW[s]);
    }
    return res;
  }
  rollingHash get(int a, int b){
    return get_len(a, b - a + 1);
  }
  rollingHashSubarrays(){
    set();
  }
  ~rollingHashSubarrays(){
    free();
  }
}
;
unsigned long long HashMap_ullP_L[4];
template<class KEY, class VAL> struct HashMap{
  char*used;
  KEY*key;
  VAL*val;
  int mem;
  int n;
  int mask;
  HashMap(){
    mem = 0;
  }
  ~HashMap(){
    free();
  }
  void expand(int nn){
    if(mem >= nn){
      return;
    }
    if(mem){
      free();
    }
    mem = nn;
    used = new char[nn];
    key = new KEY[nn];
    val = new VAL[nn];
  }
  void free(){
    if(mem){
      mem = 0;
      delete[] used;
      delete[] key;
      delete[] val;
    }
  }
  void init(int nn){
    int i;
    n = 1;
    nn = nn + (nn + 1) / 2;
    while(n < nn){
      n *= 2;
    }
    mask = n - 1;
    expand(n);
    for(i=(0);i<(n);i++){
      used[i] = 0;
    }
  }
  inline int getHash(const int a){
    unsigned long long d = a;
    d = (((d * HashMap_ullP_L[0]) >> 32) * HashMap_ullP_L[1]) & mask;
    return d;
  }
  inline int getHash(const unsigned a){
    unsigned long long d = a;
    d = (((d * HashMap_ullP_L[0]) >> 32) * HashMap_ullP_L[1]) & mask;
    return d;
  }
  inline int getHash(const long long a){
    unsigned long long d = a;
    d = (((((d * HashMap_ullP_L[0]) >> 32) * HashMap_ullP_L[1]) >> 32) * HashMap_ullP_L[2]) & mask;
    return d;
  }
  inline int getHash(const unsigned long long a){
    unsigned long long d = a;
    d = (((((d * HashMap_ullP_L[0]) >> 32) * HashMap_ullP_L[1]) >> 32) * HashMap_ullP_L[2]) & mask;
    return d;
  }
  inline int getHash(const pair<int,int> a){
    unsigned long long d = (((unsigned long long)a.first) << 32) + ((unsigned long long)a.second);
    d = (((((d * HashMap_ullP_L[0]) >> 32) * HashMap_ullP_L[1]) >> 32) * HashMap_ullP_L[2]) & mask;
    return d;
  }
  inline VAL& operator[](const KEY a){
    int k = getHash(a);
    for(;;){
      if(used[k]==1 && key[k]==a){
        break;
      }
      if(used[k]==0){
        used[k] = 1;
        key[k] = a;
        break;
      }
      k = (k+1) & mask;
    }
    return val[k];
  }
  inline bool exist(const KEY a){
    int k = getHash(a);
    for(;;){
      if(used[k]==1 && key[k]==a){
        return true;
      }
      if(used[k]==0){
        break;
      }
      k = (k+1) & mask;
    }
    return false;
  }
  template<class S> inline bool exist(const KEY a, S &res){
    int k = getHash(a);
    for(;;){
      if(used[k]==1 && key[k]==a){
        res = val[k];
        return true;
      }
      if(used[k]==0){
        break;
      }
      k = (k+1) & mask;
    }
    return false;
  }
}
;
int N;
int K;
char S[1000000+2];
char res[1000000+2];
int main(){
  int Lj4PdHRW;
  {
    rollingHashInit();
  }
  {
    int i;
    int j;
    int k;
    Rand rnd;
    for(i=(0);i<(20);i++){
      rnd.get(2);
    }
    for(i=(0);i<(4);i++){
      for(j=(0);j<(32);j++){
        k = rnd.get(1,62);
        HashMap_ullP_L[i] |= (1ULL << k);
      }
      HashMap_ullP_L[i] |= (1ULL << 0);
      HashMap_ullP_L[i] |= (1ULL << 63);
    }
  }
  HashMap<unsigned long long,int> mp;
  rollingHash h;
  rollingHashSubarrays arr;
  int KL2GvlyY = rd_int();
  for(Lj4PdHRW=(0);Lj4PdHRW<(KL2GvlyY);Lj4PdHRW++){
    int i;
    rd(N);
    rd(K);
    rd(S);
    for(i=(0);i<(N);i++){
      S[i] = (S[i] - '0') ^ 1;
    }
    arr.set(N, S);
    mp.init(N-K+1);
    for(i=(0);i<(N-K+1);i++){
      mp[arr.get_len(i,K).hs] = 1;
    }
    for(i=(0);i<(K);i++){
      res[i] = 0;
    }
    h = calcRollingHash(K, res);
    for(;;){
      int j;
      if(!mp.exist(h.hs)){
        wt_L("YES");
        wt_L('\n');
        for(i=(0);i<(K);i++){
          res[i] += '0';
        }
        res[K] = '\0';
        wt_L(res);
        wt_L('\n');
        break;
      }
      for(i=(K)-1;i>=(0);i--){
        if(res[i] == 0){
          break;
        }
      }
      if(i==-1){
        wt_L("NO");
        wt_L('\n');
        break;
      }
      res[i] = 1;
      h.change(i, 0, 1);
      for(j=(i+1);j<(K);j++){
        res[j] = 0;
        h.change(j, 1, 0);
      }
    }
  }
  return 0;
}
// cLay version 20201229-1

// --- original code ---
// //no-unlocked
// int N, K; char S[1d6+2], res[1d6+2];
// {
//   HashMap<ull,int> mp;
//   rollingHash h;
//   rollingHashSubarrays arr;
//   REP(rd_int()){
//     rd(N,K,S);
//     rep(i,N) S[i] = (S[i] - '0') ^ 1;
// 
//     arr.set(N, S);
//     mp.init(N-K+1);
//     rep(i,N-K+1) mp[arr.get_len(i,K).hs] = 1;
// 
//     rep(i,K) res[i] = 0;
//     h = calcRollingHash(K, res);
//     for(;;){
//       if(!mp.exist(h.hs)){
//         wt("YES");
//         rep(i,K) res[i] += '0';
//         res[K] = '\0';
//         wt(res);
//         break;
//       }
// 
//       rrep(i,K) if(res[i] == 0) break;
//       if(i==-1) wt("NO"), break;
//       res[i] = 1; h.change(i, 0, 1);
//       rep(j,i+1,K) res[j] = 0, h.change(j, 1, 0);
//     }
//   }
// }

```