<p>You are given a string <code>s</code> and an array of strings <code>words</code>. All the strings of <code>words</code> are of <strong>the same length</strong>.</p>

<p>A <strong>concatenated string</strong> is a string that exactly contains all the strings of any permutation of <code>words</code> concatenated.</p>

<ul>
	<li>For example, if <code>words = [&quot;ab&quot;,&quot;cd&quot;,&quot;ef&quot;]</code>, then <code>&quot;abcdef&quot;</code>, <code>&quot;abefcd&quot;</code>, <code>&quot;cdabef&quot;</code>, <code>&quot;cdefab&quot;</code>, <code>&quot;efabcd&quot;</code>, and <code>&quot;efcdab&quot;</code> are all concatenated strings. <code>&quot;acdbef&quot;</code> is not a concatenated string because it is not the concatenation of any permutation of <code>words</code>.</li>
</ul>

<p>Return an array of <em>the starting indices</em> of all the concatenated substrings in <code>s</code>. You can return the answer in <strong>any order</strong>.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>

<div class="example-block">
<p><strong>Input:</strong> <span class="example-io">s = &quot;barfoothefoobarman&quot;, words = [&quot;foo&quot;,&quot;bar&quot;]</span></p>

<p><strong>Output:</strong> <span class="example-io">[0,9]</span></p>

<p><strong>Explanation:</strong></p>

<p>The substring starting at 0 is <code>&quot;barfoo&quot;</code>. It is the concatenation of <code>[&quot;bar&quot;,&quot;foo&quot;]</code> which is a permutation of <code>words</code>.<br />
The substring starting at 9 is <code>&quot;foobar&quot;</code>. It is the concatenation of <code>[&quot;foo&quot;,&quot;bar&quot;]</code> which is a permutation of <code>words</code>.</p>
</div>

<p><strong class="example">Example 2:</strong></p>

<div class="example-block">
<p><strong>Input:</strong> <span class="example-io">s = &quot;wordgoodgoodgoodbestword&quot;, words = [&quot;word&quot;,&quot;good&quot;,&quot;best&quot;,&quot;word&quot;]</span></p>

<p><strong>Output:</strong> <span class="example-io">[]</span></p>

<p><strong>Explanation:</strong></p>

<p>There is no concatenated substring.</p>
</div>

<p><strong class="example">Example 3:</strong></p>

<div class="example-block">
<p><strong>Input:</strong> <span class="example-io">s = &quot;barfoofoobarthefoobarman&quot;, words = [&quot;bar&quot;,&quot;foo&quot;,&quot;the&quot;]</span></p>

<p><strong>Output:</strong> <span class="example-io">[6,9,12]</span></p>

<p><strong>Explanation:</strong></p>

<p>The substring starting at 6 is <code>&quot;foobarthe&quot;</code>. It is the concatenation of <code>[&quot;foo&quot;,&quot;bar&quot;,&quot;the&quot;]</code>.<br />
The substring starting at 9 is <code>&quot;barthefoo&quot;</code>. It is the concatenation of <code>[&quot;bar&quot;,&quot;the&quot;,&quot;foo&quot;]</code>.<br />
The substring starting at 12 is <code>&quot;thefoobar&quot;</code>. It is the concatenation of <code>[&quot;the&quot;,&quot;foo&quot;,&quot;bar&quot;]</code>.</p>
</div>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>1 &lt;= s.length &lt;= 10<sup>4</sup></code></li>
	<li><code>1 &lt;= words.length &lt;= 5000</code></li>
	<li><code>1 &lt;= words[i].length &lt;= 30</code></li>
	<li><code>s</code> and <code>words[i]</code> consist of lowercase English letters.</li>
</ul>

#include <bits/stdc++.h>
using namespace std;

struct Trie
{
    Trie *next[26];
    int idx;
    Trie()
    {
        int i;
        for (i = 0; i < 26; i++)
            next[i] = NULL;
        idx = -1;
    }
};

class Solution
{
    Trie *t = new Trie;
    int find(string s, int idx, bool insert = false)
    {
        Trie *cur = t;
        int i, j;
        for (i = 0; i < s.length(); i++)
        {
            j = s[i] - 'a';
            if (cur->next[j])
                cur = cur->next[j];
            else if (insert)
            {
                cur->next[j] = new Trie;
                cur = cur->next[j];
            }
            else
                return -1;
        }
        if (cur->idx == -1)
            cur->idx = idx;
        return cur->idx;
    }

public:
    vector<int> findSubstring(string s, vector<string> &words)
    {
        int i, j, cnt[5000] = {0}, uniq = 0, n = words[0].length(), m = words.size();
        int split[30][10000];
        vector<int> ans;
        for (i = 0; i < m; i++)
        {
            j = find(words[i], i, true);
            if (!cnt[j]++)
                uniq++;
        }
        for (i = 0; i < n; i++)
        {
            string buf = "";
            int k = 0, tmp[5000] = {0}, chk = 0, x = 0;
            for (j = 0; j + i < s.length(); j++)
            {
                buf = buf + s[j + i];
                if (j % n == n - 1)
                {
                    split[i][k++] = find(buf, -1);
                    buf = "";
                }
            }
            for (j = 0; j < k; j++)
            {
                if (split[i][j] != -1 && ++tmp[split[i][j]] == cnt[split[i][j]])
                    chk++;
                if (split[i][j] != -1 && tmp[split[i][j]] == cnt[split[i][j]] + 1)
                    chk--;
                if (split[i][j] == -1)
                    x++;
                if (m <= j && split[i][j - m] != -1 && --tmp[split[i][j - m]] == cnt[split[i][j - m]])
                    chk++;
                if (m <= j && split[i][j - m] != -1 && tmp[split[i][j - m]] == cnt[split[i][j - m]] - 1)
                    chk--;
                if (m <= j && split[i][j - m] == -1)
                    x--;
                if (!x && chk == uniq)
                    ans.push_back((j + 1 - m) * n + i);
            }
        }
        return ans;
    }
};
76137