<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>

class Solution {
public:

    vector<int> solve(string s, vector<string>& words, int idx) {
        vector<int> ans;
        int n = words.size();
        int m = words[0].length();
        if (s.length() < m*n) return ans;
        int tokens_in_mp = n;
        unordered_map<string,int> st,mp;
        vector<string> tokens;
        for (int i = 0; i < s.length()/m; i++) {
            tokens.push_back(s.substr(i*m,m));
        }

        for (auto w : words) {
            if (st.find(w) == st.end()) st[w] = 0;
            st[w]++;
        }

        int total_matched = 0;

        for (int i = 0; i < n; i++) {
            if (st.find(tokens[i]) != st.end()) {
                if (mp.find(tokens[i]) == mp.end()) mp[tokens[i]] = 0;
                
                mp[tokens[i]]++;
                if (mp[tokens[i]] == st[tokens[i]]) total_matched++;
                if (mp[tokens[i]] == st[tokens[i]]+1) total_matched--;
            }
        }

        if (total_matched == st.size()) ans.push_back(idx);

        for (int i = 0; i+n < tokens.size(); i++) {
            if (mp.find(tokens[i]) != mp.end()) {
                mp[tokens[i]]--;
                if (mp[tokens[i]] == st[tokens[i]]) total_matched++;
                if (mp[tokens[i]] == st[tokens[i]]-1) total_matched--;
            }
            if (st.find(tokens[i+n]) != st.end()) {
                if (mp.find(tokens[i+n]) == mp.end()) mp[tokens[i+n]] = 0;
                mp[tokens[i+n]]++;
                if (mp[tokens[i+n]] == st[tokens[i+n]]) total_matched++;
                if (mp[tokens[i+n]] == st[tokens[i+n]]+1) total_matched--;
            }
            if (total_matched == st.size()) ans.push_back((i+1)*m+idx);
        }
        return ans;
    }

    vector<int> findSubstring(string s, vector<string>& words) {
        vector<int> ans;
        if (s.length() < words.size()*words[0].length()) return ans;
        for (int i = 0; i < words[0].length(); i++) {
            vector<int> tmp = solve(s.substr(i),words,i);
            ans.insert(ans.end(),tmp.begin(),tmp.end());
        }
        return ans;
    }
};
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