Valid Parentheses

Author: TonyStark-19

Stack/ValidParentheses.cpp

@@ -0,0 +1,48 @@
+#include <iostream>
+#include <stack>
+#include <string>
+using namespace std;
+
+bool isValid(string s)
+{
+    stack<char> st;
+
+    for (int i = 0; i < s.size(); i++)
+    {
+        if (s[i] == '(' || s[i] == '{' || s[i] == '[') // opening brackets
+        {
+            st.push(s[i]);
+        }
+        else // closing bracket
+        {
+            if (st.size() == 0) // stack is empty or no opening brackets
+            {
+                return false;
+            }
+
+            if (st.top() == '(' && s[i] == ')' ||
+                st.top() == '{' && s[i] == '}' ||
+                st.top() == '[' && s[i] == ']')
+            { // match found
+                st.pop();
+            }
+            else // no match found
+            {
+                return false;
+            }
+        }
+    }
+
+    return st.size() == 0;
+}
+
+int main()
+{
+    string s1 = "()[]{}";
+    string s2 = "(]";
+
+    cout << isValid(s1) << endl;
+    cout << isValid(s2) << endl;
+
+    return 0;
+}