added Sort Array By Parity (easy)

Author: minhyeong-joe

Easy/SortArrayByParity/README.md

@@ -0,0 +1,22 @@
+
+# Sort Array By Parity
+[Leetcode Link](https://leetcode.com/problems/sort-array-by-parity/)
+
+## Problem:
+
+Given an array `A` of non-negative integers, return an array consisting of all the even elements of `A`, followed by all the odd elements of `A`.
+
+You may return any answer array that satisfies this condition.
+
+## Example:
+
+```
+Input: [3,1,2,4]
+Output: [2,4,3,1]
+The outputs [4,2,3,1], [2,4,1,3], and [4,2,1,3] would also be accepted.
+```
+
+## Note:
+
+- `1 <= A.length <= 5000`
+- `0 <= A[i] <= 5000`

Easy/SortArrayByParity/Solution.java

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+package Easy.SortArrayByParity;
+
+/**
+ * 
+ */
+public class Solution {
+
+ public int[] sortArrayByParity(int[] A) {
+ int evenIndex = -1;
+ for (int i = 0; i < A.length; i++) {
+ if (A[i] % 2 != 0) {
+ // if odd
+ // initialize first even index
+ if (evenIndex < 0) {
+ evenIndex = i;
+ }
+ while (evenIndex < A.length-1 && A[evenIndex] % 2 != 0) {
+ evenIndex++;
+ }
+ swap(A, i, evenIndex);
+ }
+ }
+ return A;
+ }
+
+ private void swap(int[] A, int i, int j) {
+ int temp = A[i];
+ A[i] = A[j];
+ A[j] = temp;
+ }
+ 
+}

Easy/SortArrayByParity/TestDriver.java

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+package Easy.SortArrayByParity;
+
+import java.util.Arrays;
+
+public class TestDriver {
+ 
+ public static void main(String[] args) {
+ Solution sol = new Solution();
+ int[] A = {3, 1, 2, 4, 5};
+ System.out.println("Output: " + Arrays.toString(sol.sortArrayByParity(A)));
+ }
+
+}

README.md

@@ -30,6 +30,7 @@ Languages used: Java and Python
  - [Shortest Unsorted Continuous Subarray](Easy/ShortedUnsortedContinuousSubarray)
  - [Find Lucky Integer in an Array](Easy/FindLuckyIntegerInArray)
  - [N-Repeated Element in Size 2N Array](Easy/N_RepeatedElementInArray)
+ - [Sort Array By Parity](Easy/SortArrayByParity)
 - Medium
  - [Minimum Add to Make Parentheses Valid](Medium/MinimumAddtoMakeParenthesesValid)
  - [Distribute Coins in Binary Tree](Medium/DistributionCoinsInBinaryTree)