905. Sort Array By Parity

Problem

Tags: Array, Two Pointers, Sorting

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]
Explanation: The outputs [4,2,3,1], [2,4,1,3], and [4,2,1,3] would also be accepted.

Example 2:

Input: nums = [0]
Output: [0]

Constraints:

• 1 <= nums.length <= 5000
• 0 <= nums[i] <= 5000

Code

C

// 905. Sort Array By Parity (5/27/54029)
// Runtime: 41 ms (41.18%) Memory: 8.89 MB (86.76%) 

int* sortArrayByParity(int nums[], int numsSize, int* returnSize) {
    int head = 0, tail = 0;
    
    while (tail < numsSize) {
        if (nums[tail] % 2 == 0) {
            int temp = nums[head];
            nums[head] = nums[tail];
            nums[tail] = temp;
            head++;
        }
        tail++;
    }
    
    *returnSize = numsSize;
    return nums;
}