Task: Given a string S, Find the longest sub string with all distinct characters. Example: Input: 1 abca Output: abc Here is the Code: Program in C++: #include<iostream> #include<bits/stdc++.h> using namespace std; int longestDistinctCharacters(string s) { map<char,int> m; int c=0,l=0; for(int i=0;i<s.length();i++) { if(m.find(s[i])==m.end()) { m[s[i]]=i; c++; } else { if(l<c) { l=c; } i=m[s[i]]; c=0; m.clear(); } } if(l<c) { l=c; } return l; } int main() { int t; cin>>t; while(t--) { string s; cin>>s; cin.ignore(); cout<<longestDistinctCharacters(s)<<endl; } return 0; } Here is the Video: