Problem Description

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.

Analyze

traverse the array，remove zero at index and append zero at last

Code

class Solution {
    func moveZeroes(inout nums: [Int]) {
        
        var zeroCount: Int = 0

        for (index, num) in nums.enumerate() {
            
            if num == 0 {
                //index was changed
                nums.removeAtIndex(index-zeroCount)
                nums.append(0)
                
                zeroCount += 1
            }
        }
    }
}