valid-parentheses solution

Author: lhc0506

valid-parentheses/lhc0506.js

@@ -0,0 +1,39 @@
+/**
+ * @param {string} s
+ * @return {boolean}
+ */
+
+const BRACKETS = {
+    SMALL_LEFT : '(',
+    SMALL_RIGHT : ')',
+    MIDIDUM_LEFT : '{',
+    MIDIDUM_RIGHT : '}',
+    LARGE_LEFT : '[',
+    LARGE_RIGHT : ']',
+};
+
+const LEFT_BRAKCETS_SET = new Set([BRACKETS.SMALL_LEFT, BRACKETS.MIDIDUM_LEFT, BRACKETS.LARGE_LEFT]);
+
+const BRACKET_MAPPER = {
+    [BRACKETS.SMALL_RIGHT]: BRACKETS.SMALL_LEFT,
+    [BRACKETS.MIDIDUM_RIGHT]: BRACKETS.MIDIDUM_LEFT,
+    [BRACKETS.LARGE_RIGHT]: BRACKETS.LARGE_LEFT,
+};
+
+var isValid = function(s) {
+    const stack = [];
+
+    for (const bracket of s) {
+        if (LEFT_BRAKCETS_SET.has(bracket)) {
+            stack.push(bracket);
+        } else {
+            const poppedBracekt = stack.pop();
+
+            if (poppedBracekt !== BRACKET_MAPPER[bracket]) {
+                return false;
+            }
+        }
+    }
+
+    return stack.length === 0;
+};