Valid Parentheses

Author: TonyKim9401

valid-parentheses/TonyKim9401.java

@@ -0,0 +1,18 @@
+// TC: O(n)
+// -> n = s.length
+// SC: O(n)
+// -> n = s.length / 2
+class Solution {
+    public boolean isValid(String s) {
+        Stack<Character> stack = new Stack<>();
+
+        for (char c : s.toCharArray()) {
+            if (c == '(') stack.add(')');
+            else if (c == '{') stack.add('}');
+            else if (c == '[') stack.add(']');
+            else if (stack.isEmpty() || stack.pop() != c) return false;
+        }
+
+        return stack.isEmpty();
+    }
+}