feat: add a solution for the daily problem of S0075

README.md

@@ -36,6 +36,7 @@ Contributions are welcome! If you have a more efficient solution or want to add
 | 67     | Add Binary                                             | 1 ms    | 42.4 MB  | [Problem](src/main/java/com/anthonyschuijlenburg/S0067/Problem.md) |
 | 69     | Sqrt(x)                                                | 1 ms    | 40.9 MB  | [Problem](src/main/java/com/anthonyschuijlenburg/S0069/Problem.md) |
 | 70     | Climbing Stairs                                        | 1 ms    | 39.8 MB  | [Problem](src/main/java/com/anthonyschuijlenburg/S0070/Problem.md) |
+| 75     | Sort Colors                                            | 1 ms    | 41.5 MB  | [Problem](src/main/java/com/anthonyschuijlenburg/S0075/Problem.md) |
 | 83     | Remove Duplicates from Sorted List                     | 0 ms    | 43.5 MB  | [Problem](src/main/java/com/anthonyschuijlenburg/S0083/Problem.md) |
 | 88     | Merge Sorted Array                                     | 0 ms    | 41.8 MB  | [Problem](src/main/java/com/anthonyschuijlenburg/S0088/Problem.md) |
 | 94     | Binary Tree Inorder Traversal                          | 0 ms    | 41.3 MB  | [Problem](src/main/java/com/anthonyschuijlenburg/S0094/Problem.md) |

src/main/java/com/anthonyschuijlenburg/S0075/Problem.md

@@ -0,0 +1,25 @@
+# 75. Sort Colors
+
+Topics: Array, Two Pointers, Sorting
+
+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.
+
+### Example 1:
+
+Input: nums = [2,0,2,1,1,0]
+Output: [0,0,1,1,2,2]
+
+### Example 2:
+
+Input: nums = [2,0,1]
+Output: [0,1,2]
+
+### Constraints:
+
+    n == nums.length
+    1 <= n <= 300
+    nums[i] is either 0, 1, or 2.

src/main/java/com/anthonyschuijlenburg/S0075/Solution.java

@@ -0,0 +1,20 @@
+package com.anthonyschuijlenburg.S0075;
+
+import java.util.Arrays;
+import java.util.HashMap;
+
+public class Solution {
+    public void sortColors(int[] nums) {
+        HashMap<Integer, Integer> map = new HashMap<>();
+
+        for (int num : nums) {
+            map.put(num, map.getOrDefault(num, 0) + 1);
+        }
+
+        int counter = 0;
+        for (int key : map.keySet()) {
+            Arrays.fill(nums, counter, counter + map.get(key), key);
+            counter += map.get(key);
+        }
+    }
+}

src/test/java/com/anthonyschuijlenburg/S0075/SolutionTest.java

@@ -0,0 +1,61 @@
+package com.anthonyschuijlenburg.S0075;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class SolutionTest {
+    @Test
+    void climbStairs_testCase0() {
+        Solution solutionGenerator = new Solution();
+        int[] arr = new int[]{0};
+        solutionGenerator.sortColors(arr);
+
+        assertArrayEquals(new int[]{0}, arr);
+    }
+
+    @Test
+    void climbStairs_testCase1() {
+        Solution solutionGenerator = new Solution();
+        int[] arr = new int[]{1};
+        solutionGenerator.sortColors(arr);
+
+        assertArrayEquals(new int[]{1}, arr);
+    }
+
+    @Test
+    void climbStairs_testCase2() {
+        Solution solutionGenerator = new Solution();
+        int[] arr = new int[]{0, 1, 2};
+        solutionGenerator.sortColors(arr);
+
+        assertArrayEquals(new int[]{0, 1, 2}, arr);
+    }
+
+    @Test
+    void climbStairs_testCase3() {
+        Solution solutionGenerator = new Solution();
+        int[] arr = new int[]{2, 1, 0};
+        solutionGenerator.sortColors(arr);
+
+        assertArrayEquals(new int[]{0, 1, 2}, arr);
+    }
+
+    @Test
+    void climbStairs_testCase4() {
+        Solution solutionGenerator = new Solution();
+        int[] arr = new int[]{2, 0, 2, 1, 1, 0};
+        solutionGenerator.sortColors(arr);
+
+        assertArrayEquals(new int[]{0, 0, 1, 1, 2, 2}, arr);
+    }
+
+    @Test
+    void climbStairs_testCase5() {
+        Solution solutionGenerator = new Solution();
+        int[] arr = new int[]{2, 0, 1};
+        solutionGenerator.sortColors(arr);
+
+        assertArrayEquals(new int[]{0, 1, 2}, arr);
+    }
+}