Leetcode day1

leetcode/lc3/UsingCharSet.cpp

@@ -0,0 +1,22 @@
+class Solution{
+    public:
+        int LengthOfLongestSubString(string s){
+            int n = s.length();
+            int maxlen = 0;
+            unordered_set<char> charset;
+            int left = 0;
+
+            for(int right = 0;right<n;right++){
+                if(charset.count(s[right])==0){
+                    charset.insert(s[right]);
+                    maxlen = max(maxlen, right-left+1);
+                }while(charset.count(s[right])){
+                    charset.erase(s[left]);
+                    left++;
+                }
+            }
+            return maxlen;
+
+
+        }
+}