add: validParentheses solution

Author: Cyjin-jani

valid-parentheses/Cyjin-jani.js

@@ -0,0 +1,34 @@
+// tc: O(n)
+// sc: O(n)
+const isValid = function (s) {
+  const bracketMap = {
+    '(': ')',
+    '{': '}',
+    '[': ']',
+  };
+
+  if (s.length % 2 !== 0 || isCloseBracket(s[0])) return false;
+
+  const stack = [];
+
+  for (let i = 0; i < s.length; i++) {
+    if (stack.length === 0) {
+      stack.push(s[i]);
+      continue;
+    }
+
+    let topBracket = stack.pop();
+    if (bracketMap[topBracket] !== s[i]) {
+      stack.push(topBracket);
+      stack.push(s[i]);
+    }
+  }
+
+  return stack.length === 0;
+};
+
+function isCloseBracket(char) {
+  const closeBrackets = [')', '}', ']'];
+
+  return closeBrackets.includes(char);
+}