Leetcode-283: moveZeroes

 solution_1:

class Solution {
public:
    void moveZeroes(vector<int>& nums) {
        int k = 0; // k # number of zero element
        for(int i = 0; i < nums.size(); i++){
            if(nums[i] != 0){
                nums[k++] = nums[i];
            }
        }
        for(; k < nums.size(); k++){
            nums[k] = 0;
        }
    }
};

 solution_2:

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

    }
};

solution_3:

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

solution3 看似最蠢，其实是最快的