Merge pull request kothariji#423 from Sparty-v6/master

Added problem 3 of leetcode TOP

Author: kothariji

Leetcode - Top Interview Questions/3. Longest Substring Without Repeating Characters.cpp

@@ -0,0 +1,35 @@
+#include<bits/stdc++.h>
+using namespace std;
+#define IO() ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL)
+
+int lengthOfLongestSubstring(string str) {
+    int left = 0;
+    int right = 0;
+    int maxx = 0;
+
+    set<char> s;
+
+    while(right < str.size()){
+    	if( s.find(str[right]) == s.end() ) {
+    		s.insert(str[right]);
+    		right++;
+    		int size = s.size();
+    		maxx = std::max(size,maxx);
+    	}
+    	else{
+    		s.erase(str[left]);
+	    	left++;
+	    }
+    }
+    return maxx;
+}
+
+int main(){
+
+	IO();
+
+	string s = "abcabcbb";
+	cout<<lengthOfLongestSubstring(s);
+
+	return 0;
+}