Move Zeroes

题目描述:
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.

这个题思路很简单,找到第一个0的起始位置和从这个0开始后面连续0的个数,将后面的数全部都往前移就行了。

代码如下:

public void moveZeroes(int[] nums) {
    int indexOf0=0,numberOf0=0;
    //前面有没有0
    boolean beforeHave0=false;      
    for (int i = 0; i < nums.length; i++) {
        if(nums[i]==0){
            if(!beforeHave0){
                indexOf0=i;
                beforeHave0=true;
            }
            numberOf0++;
        }
        if(beforeHave0&&nums[i]!=0){
            move(nums, indexOf0, numberOf0);
            //移动后初始状态要恢复过来
            numberOf0=0;
            beforeHave0=false;
            i=indexOf0;//这里不能+1
        }
    }
}

public void move(int[] nums,int indexOf0,int numberOf0){
    int i=indexOf0+numberOf0;
    if(i==nums.length)
        return ;
    for (;i<nums.length;) 
        nums[indexOf0++]=nums[i++];
    for (int j = nums.length-numberOf0; j < nums.length; j++) 
        nums[j]=0;
}

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