【排序算法模板】归并排序

#include <iostream>
#include <vector>
using namespace std;

void Merge(vector<int>& nums, const int first, const int mid, const int last, vector<int>&temp)
{
    int begin1 = first, end1 = mid;
    int begin2 = mid + 1, end2 = last;
    int cnt = 0;

    while(begin1 <= end1 && begin2 <= end2)
    {
        if(nums[begin1] <= nums[begin2])
            temp[cnt++] = nums[begin1++];
        else
            temp[cnt++] = nums[begin2++];
    }

    while(begin1 <= end1)
        temp[cnt++] = nums[begin1++];

    while(begin2 <= end2)
        temp[cnt++] = nums[begin2++];

    for(int i = 0; i < cnt; i++)
        nums[first + i] = temp[i];
}

void MergeSort(vector<int>& nums, const int first, const int last, vector<int>& temp)
{
    if(first < last)
    {
        int mid = (last + first) / 2;

        MergeSort(nums, first, mid, temp);
        MergeSort(nums, mid + 1, last, temp);
        Merge(nums, first, mid, last, temp);
    }
}

int main()
{
    int a[] = {23, 34, 45, 78, 90, 12, 49, 92, 32, 19};

    vector<int> nums(a, a + 10);
    vector<int> temp(10, 0);

    MergeSort(nums, 0, 9, temp);

    for(int i = 0; i < nums.size(); i++)
        cout<<nums[i]<<" ";
    cout<<endl;
}