Arrays: 905. Sort Array By Parity

Author: shaikrasheed99

.talismanrc

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+fileignoreconfig:
+- filename: src/arrays/easy/SortArrayByParity.java
+  checksum: b8c133e71c80cf6b4d4354d6316099b2da88a22ef24e6ccd46e043ccf908cc1f
+version: ""

src/arrays/easy/SortArrayByParity.java

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+package arrays.easy;
+
+import java.util.Arrays;
+
+/***
+ * Problem 905 in Leetcode: https://leetcode.com/problems/sort-array-by-parity/
+ *
+ * Given an integer array nums, move all the even integers at the beginning of the array followed by all the odd integers.
+ * Return any array that satisfies this condition.
+ *
+ * Example 1:
+ * Input: nums = [3,1,2,4]
+ * Output: [2,4,3,1]
+ *
+ * Example 2:
+ * Input: nums = [0]
+ * Output: [0]
+ */
+
+public class SortArrayByParity {
+    public static void main(String[] args) {
+        int[] nums = {3, 1, 2, 4};
+
+        System.out.println("Even and Odd arrays approach: " + Arrays.toString(sortArray(nums)));
+        System.out.println("Two Pass approach: " + Arrays.toString(sortArrayTwoPass(nums)));
+        System.out.println("In place approach: " + Arrays.toString(sortArrayInPlace(nums)));
+    }
+
+    private static int[] sortArray(int[] nums) {
+        int n = nums.length;
+        int[] evens = new int[n];
+        int[] odds = new int[n];
+        int even = 0, odd = 0;
+
+        for (int num : nums) {
+            if ((num & 1) == 0) {
+                evens[even++] = num;
+            } else {
+                odds[odd++] = num;
+            }
+        }
+
+        int[] result = new int[n];
+        int index = 0, traverse = 0;
+
+        while (traverse < even) {
+            result[index++] = evens[traverse++];
+        }
+
+        traverse = 0;
+
+        while (traverse < odd) {
+            result[index++] = odds[traverse++];
+        }
+
+        return result;
+    }
+
+    private static int[] sortArrayTwoPass(int[] nums) {
+        int[] result = new int[nums.length];
+        int index = 0;
+
+        for (int num : nums) {
+            if ((num & 1) == 0) {
+                result[index++] = num;
+            }
+        }
+
+        for (int num : nums) {
+            if ((num & 1) == 1) {
+                result[index++] = num;
+            }
+        }
+
+        return result;
+    }
+
+    private static int[] sortArrayInPlace(int[] nums) {
+        int start = 0, end = nums.length - 1;
+
+        while (start < end) {
+            if ((nums[start] & 1) == 1) {
+                swap(nums, start, end);
+                end--;
+            } else if ((nums[end] & 1) == 0) {
+                swap(nums, start, end);
+                start++;
+            } else {
+                start++;
+                end--;
+            }
+        }
+
+        return nums;
+    }
+
+    private static void swap(int[] nums, int start, int end) {
+        int temp = nums[start];
+        nums[start] = nums[end];
+        nums[end] = temp;
+    }
+}