Add solution #2384

Author: JoshCrozier

README.md

@@ -2162,6 +2162,7 @@
 2381|[Shifting Letters II](./solutions/2381-shifting-letters-ii.js)|Medium|
 2382|[Maximum Segment Sum After Removals](./solutions/2382-maximum-segment-sum-after-removals.js)|Hard|
 2383|[Minimum Hours of Training to Win a Competition](./solutions/2383-minimum-hours-of-training-to-win-a-competition.js)|Easy|
+2384|[Largest Palindromic Number](./solutions/2384-largest-palindromic-number.js)|Medium|
 2385|[Amount of Time for Binary Tree to Be Infected](./solutions/2385-amount-of-time-for-binary-tree-to-be-infected.js)|Medium|
 2387|[Median of a Row Wise Sorted Matrix](./solutions/2387-median-of-a-row-wise-sorted-matrix.js)|Medium|
 2389|[Longest Subsequence With Limited Sum](./solutions/2389-longest-subsequence-with-limited-sum.js)|Easy|

solutions/2384-largest-palindromic-number.js

@@ -0,0 +1,50 @@
+/**
+ * 2384. Largest Palindromic Number
+ * https://leetcode.com/problems/largest-palindromic-number/
+ * Difficulty: Medium
+ *
+ * You are given a string num consisting of digits only.
+ *
+ * Return the largest palindromic integer (in the form of a string) that can be formed
+ * using digits taken from num. It should not contain leading zeroes.
+ *
+ * Notes:
+ * - You do not need to use all the digits of num, but you must use at least one digit.
+ * - The digits can be reordered.
+ */
+
+/**
+ * @param {string} num
+ * @return {string}
+ */
+var largestPalindromic = function(num) {
+  const digitCount = new Array(10).fill(0);
+
+  for (const digit of num) {
+    digitCount[parseInt(digit, 10)]++;
+  }
+
+  let leftHalf = '';
+  let middle = '';
+  for (let digit = 9; digit >= 0; digit--) {
+    const count = digitCount[digit];
+    const pairs = Math.floor(count / 2);
+
+    if (digit === 0 && leftHalf === '') {
+      continue;
+    }
+
+    leftHalf += digit.toString().repeat(pairs);
+
+    if (count % 2 === 1 && middle === '') {
+      middle = digit.toString();
+    }
+  }
+
+  if (leftHalf === '' && middle === '') {
+    return '0';
+  }
+
+  const rightHalf = leftHalf.split('').reverse().join('');
+  return leftHalf + middle + rightHalf;
+};