poj 3302 Subsequence

#include <iostream>#include <string>#include <algorithm>using namespace std;bool isSubStr(string str1, string str2) {    char c;    string::size_type pos = 0;    string::size_type ix = 0;    for(; ix != str2.size(); ++ix) {        c = str2[ix];        pos = str1.find(c, pos);          if(pos == string::npos)  break;        else str1.erase(pos, 1);     }    if(ix == str2.size())        return true;    else        return false;}int main(){    int n;    cin >> n;    string str1, str2;    for(int i = 0; i < n; ++i) {        cin >> str1 >> str2;        string str2_backup = str2;        reverse(str2.begin(), str2.end());        if(isSubStr(str1, str2) || isSubStr(str1, str2_backup)) cout << "YES" << endl;        else cout << "NO" << endl;    }    return 0;}