Task: Given a string S. Find the first repeated character in it. Example: Input: 1 geeksforgeeks Output: e // first repeated character and second time occurred character index is smallest. Here is the Code: Program in C++: #include<iostream> #include<bits/stdc++.h> using namespace std; int main() { int t; cin>>t; while(t--) { string s; cin>>s; map<char,int> m; int c=0; for(int i=0;i<s.length();i++) { m[s[i]]++; if(m[s[i]]==2) { cout<<s[i]<<endl; c=1; break; } } if(c==0) { cout<<-1<<endl; } } return 0; } Here is the Video: