3. Longest Substring Without Repeating Characters

C++ | 100% Success | Simple Approach

class Solution {
public:
	int lengthOfLongestSubstring(string s) {
			   unordered_map<char,int> mp;
		int start=0,maxlength=0;
		for(int i=0;i<s.length();i++){
			mp[s[i]]++;
			if(mp[s[i]]>1){
				while(start< s.length() && mp[s[i]]>1)
				{
					mp[s[start]]--;
					start++;
				}
			}
			maxlength=max(maxlength,i-start+1);
		}
		return maxlength;

	}
};