Add solution #2002

Author: JoshCrozier

README.md

@@ -1,4 +1,4 @@
-# 1,680 LeetCode solutions in JavaScript
+# 1,681 LeetCode solutions in JavaScript
 
 [https://leetcodejavascript.com](https://leetcodejavascript.com)
 
@@ -1536,6 +1536,7 @@
 1998|[GCD Sort of an Array](./solutions/1998-gcd-sort-of-an-array.js)|Hard|
 2000|[Reverse Prefix of Word](./solutions/2000-reverse-prefix-of-word.js)|Easy|
 2001|[Number of Pairs of Interchangeable Rectangles](./solutions/2001-number-of-pairs-of-interchangeable-rectangles.js)|Medium|
+2002|[Maximum Product of the Length of Two Palindromic Subsequences](./solutions/2002-maximum-product-of-the-length-of-two-palindromic-subsequences.js)|Medium|
 2011|[Final Value of Variable After Performing Operations](./solutions/2011-final-value-of-variable-after-performing-operations.js)|Easy|
 2016|[Maximum Difference Between Increasing Elements](./solutions/2016-maximum-difference-between-increasing-elements.js)|Easy|
 2017|[Grid Game](./solutions/2017-grid-game.js)|Medium|

solutions/2002-maximum-product-of-the-length-of-two-palindromic-subsequences.js

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+/**
+ * 2002. Maximum Product of the Length of Two Palindromic Subsequences
+ * https://leetcode.com/problems/maximum-product-of-the-length-of-two-palindromic-subsequences/
+ * Difficulty: Medium
+ *
+ * Given a string s, find two disjoint palindromic subsequences of s such that the product of their
+ * lengths is maximized. The two subsequences are disjoint if they do not both pick a character at
+ * the same index.
+ *
+ * Return the maximum possible product of the lengths of the two palindromic subsequences.
+ *
+ * A subsequence is a string that can be derived from another string by deleting some or no
+ * characters without changing the order of the remaining characters. A string is palindromic
+ * if it reads the same forward and backward.
+ */
+
+/**
+ * @param {string} s
+ * @return {number}
+ */
+var maxProduct = function(s) {
+  const n = s.length;
+  let result = 0;
+
+  for (let mask1 = 1; mask1 < (1 << n); mask1++) {
+    for (let mask2 = 1; mask2 < (1 << n); mask2++) {
+      if (mask1 & mask2) continue;
+      const len1 = isPalindrome(s, mask1);
+      if (len1 === 0) continue;
+      const len2 = isPalindrome(s, mask2);
+      if (len2 === 0) continue;
+      result = Math.max(result, len1 * len2);
+    }
+  }
+
+  return result;
+
+  function isPalindrome(str, mask) {
+    const chars = [];
+    for (let i = 0; i < n; i++) {
+      if (mask & (1 << i)) chars.push(str[i]);
+    }
+    let left = 0;
+    let right = chars.length - 1;
+    while (left < right) {
+      if (chars[left++] !== chars[right--]) return 0;
+    }
+    return chars.length;
+  }
+};