Create yeonguchoe.cs

Author: YeonguChoe

valid-parentheses/yeonguchoe.cs

@@ -0,0 +1,24 @@
+public class Solution {
+    public bool IsValid(string s) {
+        Stack<char> parentheses = new Stack<char>();
+        
+        Dictionary<char, char> pair = new Dictionary<char, char> {
+            { ')', '(' },
+            { '}', '{' },
+            { ']', '[' }
+        };
+
+        foreach (char c in s) {
+            if (c == '(' || c == '{' || c == '[') {
+                parentheses.Push(c);
+            } 
+            else if (c == ')' || c == '}' || c == ']') {
+                if (parentheses.Count == 0 || parentheses.Peek() != pair[c]) {
+                    return false;
+                }
+                parentheses.Pop();
+            }
+        }
+
+        return parentheses.Count == 0;
+    }