Update and rename ValidParanthesis.cpp to easy-20-valid_parentheses.cpp

Author: matthewgoembel

Codes/ValidParanthesis.cpp

@@ -0,0 +1,43 @@
+// Given a string s containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid.
+
+// An input string is valid if:
+
+// Open brackets must be closed by the same type of brackets.
+// Open brackets must be closed in the correct order.
+// Every close bracket has a corresponding open bracket of the same type.
+ 
+
+// Example 1:
+
+// Input: s = "()"
+// Output: true
+
+// Example 2:
+
+// Input: s = "()[]{}"
+// Output: true
+
+// Example 3:
+
+// Input: s = "(]"
+// Output: false
+
+
+class Solution {
+public:
+	bool isValid(string s) {
+		stack<char> yes;
+		yes.push(s[0]);
+		for (int i = 1; s[i] != NULL; i++) {
+            if(yes.empty()&&(s[i]==']'||s[i]=='}'||s[i]==')'))
+                return false;
+			if ((s[i] == ')' && yes.top()=='(')||(s[i] == ']' && yes.top()=='[')||(s[i] == '}' && yes.top()=='{')) {
+				yes.pop();
+			}
+			else {
+				yes.push(s[i]);
+			}
+		}
+		return yes.empty();
+	}
+};