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leetcode 283_movezeroes

admin 11月 12, 2020 0

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.

Solution

一个比较普适的解法，与快排相似，两个指针扫描，不过都是从头开始扫描，一个指针检测非零，一个指针检测零，都检测到时就交换。

class Solution {
public:
    void (vector<int>& nums) {
        int index = 0;
        int zero = 0;
        while(zero<nums.size()){
            if(nums[zero] != 0 && nums[index] == 0){
                for(int i = zero;i> index;i--){swap(nums[i],nums[i-1]);}
            }
            if(nums[zero] == 0  || (nums[zero]!=0 && zero<=index))zero++;
            if(nums[index] != 0)index++;
        }
    }
};

另一种解法，直接将非零的往前排，到最后再赋0值。

class Solution {
public:
    void (vector<int>& nums) {
        int j = 0;
        for(int i =0; i< nums.size();i++){
            if(nums[i] != 0){
                nums[j++] = nums[i];
            }
        }
        for(;j<nums.size();j++){
            nums[j] = 0;
        }
    }
};