Merge pull request larissalages#155 from MariamFahmy98/newProblem

Adding new Leetcode Probem

Author: larissalages

leetcode/cpp/Stacks/20.cpp

@@ -0,0 +1,24 @@
+class Solution {
+    bool checkingOpen(char ch) {
+    return ch == '(' || ch == '[' || ch == '{';
+    }
+    char checkBracket(char ch){
+        if(ch == ']') return '[';
+        else if(ch == '}') return '{';
+        else return '(';
+    }
+public:
+    bool isValid(string s) {
+        stack <char> st;
+       for(int i = 0 ; i < s.length() ; i++){
+           if(checkingOpen(s[i])) st.push(s[i]);
+           else{
+              if(st.empty()) return false;
+              if(checkBracket(s[i]) == st.top()) st.pop();
+              else return false;
+           }
+       } 
+        if(st.empty()) return true;
+        else return false;
+    }
+};