Add solution #2231

Author: JoshCrozier

README.md

@@ -2024,6 +2024,7 @@
 2226|[Maximum Candies Allocated to K Children](./solutions/2226-maximum-candies-allocated-to-k-children.js)|Medium|
 2227|[Encrypt and Decrypt Strings](./solutions/2227-encrypt-and-decrypt-strings.js)|Hard|
 2229|[Check if an Array Is Consecutive](./solutions/2229-check-if-an-array-is-consecutive.js)|Easy|
+2231|[Largest Number After Digit Swaps by Parity](./solutions/2231-largest-number-after-digit-swaps-by-parity.js)|Easy|
 2232|[Minimize Result by Adding Parentheses to Expression](./solutions/2232-minimize-result-by-adding-parentheses-to-expression.js)|Medium|
 2234|[Maximum Total Beauty of the Gardens](./solutions/2234-maximum-total-beauty-of-the-gardens.js)|Hard|
 2235|[Add Two Integers](./solutions/2235-add-two-integers.js)|Easy|

solutions/2231-largest-number-after-digit-swaps-by-parity.js

@@ -0,0 +1,45 @@
+/**
+ * 2231. Largest Number After Digit Swaps by Parity
+ * https://leetcode.com/problems/largest-number-after-digit-swaps-by-parity/
+ * Difficulty: Easy
+ *
+ * You are given a positive integer num. You may swap any two digits of num that have the
+ * same parity (i.e. both odd digits or both even digits).
+ *
+ * Return the largest possible value of num after any number of swaps.
+ */
+
+/**
+ * @param {number} num
+ * @return {number}
+ */
+var largestInteger = function(num) {
+  const digits = num.toString().split('').map(Number);
+  const evenDigits = [];
+  const oddDigits = [];
+
+  for (const digit of digits) {
+    if (digit % 2 === 0) {
+      evenDigits.push(digit);
+    } else {
+      oddDigits.push(digit);
+    }
+  }
+
+  evenDigits.sort((a, b) => b - a);
+  oddDigits.sort((a, b) => b - a);
+
+  let evenIndex = 0;
+  let oddIndex = 0;
+  const result = [];
+
+  for (const digit of digits) {
+    if (digit % 2 === 0) {
+      result.push(evenDigits[evenIndex++]);
+    } else {
+      result.push(oddDigits[oddIndex++]);
+    }
+  }
+
+  return parseInt(result.join(''), 10);
+};