Add valid-parentheses solution in TypeScript

Author: Jeehay28

valid-parentheses/Jeehay28.ts

@@ -0,0 +1,26 @@
+// Time Complexity: O(n)
+// Space Complexity: O(n)
+
+function isValid(s: string): boolean {
+  const map = new Map<string, string>([
+    ["(", ")"],
+    ["{", "}"],
+    ["[", "]"],
+  ]);
+
+  let stack: string[] = [];
+
+  for (const ch of s) {
+    if (map.has(ch)) {
+      stack.push(ch);
+    } else {
+      const last = stack.pop();
+      if (!last || ch !== map.get(last)) {
+        return false;
+      }
+    }
+  }
+
+  return stack.length === 0;
+}
+