Move Zeroes

Given an array nums, write a function to move all 0's to the end of it while maintaining the relative order of the non-zero elements.

For example, given nums = [0, 1, 0, 3, 12], after calling your function, nums should be [1, 3, 12, 0, 0].

Note:

You must do this in-place without making a copy of the array. Minimize the total number of operations.

Credits:Special thanks to @jianchao.li.fighter for adding this problem and creating all test cases.

Solution

public class Solution {
   public void moveZeroes(int[] nums) {
        if (nums == null || nums.length == 0) return;
        int end = 0;
        int start = 1;

        while (start < nums.length) {
            if (nums[start] == 0 ) {
                if (nums[end] != 0) {
                    end = start;
                }

            } else {
                if (nums[end] == 0) {
                    change(nums, start, end);
                    end++;
                }

            }

            start++;
        }
    }

    public void change(int[] nums, int m, int n) {
        int temp = nums[m];
        nums[m] = nums[n];
        nums[n] = temp;
    }
}