[LeetCode] 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:

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

Sol. Find non-zero items and move it to the head of array. Use another index for pointing to the next non-zero place.

public void moveZeroes(int[] nums) {

        for (int i = 0, cursor = 0; i < nums.length; i++) {

            if (nums[i] != 0) {

                nums[cursor] = nums[i];

                if (cursor != i) nums[i] = 0;

                cursor++;

            }

        }

}

Time Complexity: O(n), n stands for the length of the array.

Space Complexity: O(1), one index for next non-zero place.