js-concepts: leetcode prob.678 - Valid parenthesis string with stars

Author: baochau.dinh

LeetCode/678. Valid Parenthesis String/index.js

@@ -0,0 +1,22 @@
+var checkValidString = function(s) {
+  let diff = 0;
+  for (let i = 0; i < s.length; i++) {
+      if (s[i] === '(' || s[i] === '*') diff++
+      else diff--
+      if (diff < 0) return false;
+  }
+  if (diff === 0) return true
+  
+  diff = 0;
+  for (let i = s.length - 1; i >= 0; i--) {
+      if (s[i] === ')' || s[i] === '*') diff++
+      else diff--
+      if (diff < 0) return false;
+  }
+  return true;
+};
+
+var checkValidStringV2 = function(s) {
+  let diff = 0;
+  let first = 0, second = s.length - 1;
+}