Add solution #75

Author: JoshCrozier

README.md

@@ -74,6 +74,7 @@
 70|[Climbing Stairs](./0070-climbing-stairs.js)|Easy|
 73|[Set Matrix Zeroes](./0073-set-matrix-zeroes.js)|Medium|
 74|[Search a 2D Matrix](./0074-search-a-2d-matrix.js)|Medium|
+75|[Sort Colors](./0075-sort-colors.js)|Medium|
 77|[Combinations](./0077-combinations.js)|Medium|
 78|[Subsets](./0078-subsets.js)|Medium|
 80|[Remove Duplicates from Sorted Array II](./0080-remove-duplicates-from-sorted-array-ii.js)|Medium|

solutions/0075-sort-colors.js

@@ -0,0 +1,28 @@
+/**
+ * 75. Sort Colors
+ * https://leetcode.com/problems/sort-colors/
+ * Difficulty: Medium
+ *
+ * Given an array nums with n objects colored red, white, or blue, sort them in-place so
+ * that objects of the same color are adjacent, with the colors in the order red, white,
+ * and blue.
+ *
+ * We will use the integers 0, 1, and 2 to represent the color red, white, and blue,
+ * respectively.
+ *
+ * You must solve this problem without using the library's sort function.
+ */
+
+/**
+ * @param {number[]} nums
+ * @return {void} Do not return anything, modify nums in-place instead.
+ */
+var sortColors = function(nums) {
+  const count = nums.reduce((a, n) => ++a[n] && a, [0, 0, 0]);
+  for (let i = 0, j = 0; i < count.length; i++) {
+    for (let k = 0; k < count[i]; k++) {
+      nums[j++] = i;
+    }
+  }
+  return nums;
+};