Add solution #1542

Author: JoshCrozier

README.md

@@ -1,4 +1,4 @@
-# 1,356 LeetCode solutions in JavaScript
+# 1,357 LeetCode solutions in JavaScript
 
 [https://leetcodejavascript.com](https://leetcodejavascript.com)
 
@@ -1178,6 +1178,7 @@
 1539|[Kth Missing Positive Number](./solutions/1539-kth-missing-positive-number.js)|Easy|
 1540|[Can Convert String in K Moves](./solutions/1540-can-convert-string-in-k-moves.js)|Medium|
 1541|[Minimum Insertions to Balance a Parentheses String](./solutions/1541-minimum-insertions-to-balance-a-parentheses-string.js)|Medium|
+1542|[Find Longest Awesome Substring](./solutions/1542-find-longest-awesome-substring.js)|Hard|
 1550|[Three Consecutive Odds](./solutions/1550-three-consecutive-odds.js)|Easy|
 1551|[Minimum Operations to Make Array Equal](./solutions/1551-minimum-operations-to-make-array-equal.js)|Medium|
 1566|[Detect Pattern of Length M Repeated K or More Times](./solutions/1566-detect-pattern-of-length-m-repeated-k-or-more-times.js)|Easy|

solutions/1542-find-longest-awesome-substring.js

@@ -0,0 +1,41 @@
+/**
+ * 1542. Find Longest Awesome Substring
+ * https://leetcode.com/problems/find-longest-awesome-substring/
+ * Difficulty: Hard
+ *
+ * You are given a string s. An awesome substring is a non-empty substring of s such that we
+ * can make any number of swaps in order to make it a palindrome.
+ *
+ * Return the length of the maximum length awesome substring of s.
+ */
+
+/**
+ * @param {string} s
+ * @return {number}
+ */
+var longestAwesome = function(s) {
+  let result = 0;
+  let prefixMask = 0;
+  const digitMasks = new Map();
+  digitMasks.set(0, -1);
+
+  for (let i = 0; i < s.length; i++) {
+    const digit = s.charCodeAt(i) - '0'.charCodeAt(0);
+    prefixMask ^= (1 << digit);
+
+    if (digitMasks.has(prefixMask)) {
+      result = Math.max(result, i - digitMasks.get(prefixMask));
+    } else {
+      digitMasks.set(prefixMask, i);
+    }
+
+    for (let j = 0; j < 10; j++) {
+      const oddMask = prefixMask ^ (1 << j);
+      if (digitMasks.has(oddMask)) {
+        result = Math.max(result, i - digitMasks.get(oddMask));
+      }
+    }
+  }
+
+  return result;
+};