valid-parentheses

Author: taewanseoul

valid-parentheses/taewanseoul.ts

@@ -0,0 +1,30 @@
+/**
+ * 20. Valid Parentheses
+ * Given a string s containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid.
+ *
+ * An input string is valid if:
+ * 1. Open brackets must be closed by the same type of brackets.
+ * 2. Open brackets must be closed in the correct order.
+ * 3. Every close bracket has a corresponding open bracket of the same type.
+ *
+ * https://leetcode.com/problems/valid-parentheses/
+ *
+ */
+
+// O(n^2) time
+// O(1) space
+function isValid(s: string): boolean {
+  if (s.length % 2 === 1) return false;
+
+  while (
+    s.indexOf("()") !== -1 ||
+    s.indexOf("{}") !== -1 ||
+    s.indexOf("[]") !== -1
+  ) {
+    s = s.replace("()", "");
+    s = s.replace("{}", "");
+    s = s.replace("[]", "");
+  }
+
+  return s === "";
+}