Leetcode 283：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.

 

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

 

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题目解析：

 

对数组进行操作的题。

 

需要有一个index来作为维护的指针，一个count来计算数组中有多少个0。

 

使用一个for循序遍历数组，然后判断当前位置是否为0：

1. 为0，count++

2. 不为0，将值重新填入index位，index++

 

当循环结束的时候，将所有的0填入index之后的所有位置上。

 

public void moveZeroes(int[] nums) {
        int count = 0;
        int index = 0;
        for(int i = 0; i < nums.length; i++){
            if(nums[i] == 0){
                count++;
            }else{
                nums[index] = nums[i];
                index++;
            }
        }
        for(int k = 1; k <= count; k++){
            nums[k + index - 1] = 0;
        }
    }