归并排序模版

 

#include <iostream>
#include <vector>
#include <algorithm>
#include <string>
#include <cstdio>
using namespace std;
int a[100010];
int temp[100010];
void Merge(int l, int mid, int r) {
    for (int i = l; i <= r; i++) temp[i] = a[i];
    int i = l, j = mid + 1, k = l;
    while (i <= mid && j <= r) {
        if (temp[i] <= temp[j]) {
            a[k++] = temp[i++];
        }else {
            a[k++] = temp[j++];
        }
    }
    while (i <= mid) a[k++] = temp[i++];
    while (j <= r) a[k++] = temp[j++];
}
void Mergesort(int l, int r) {
    if (l >= r) return;
    int mid = (l+r) / 2;
    Mergesort(l,  mid);
    Mergesort(mid+1, r);
    Merge(l, mid, r);
}

int main()
{
    int n, m;
    while (cin >> n)
    {
        if (n == 0)break;
        cin >> m;
        for (int i = 0; i < n; i++)
        {
            cin >> a[i];
        }
        //quick_sort(a, 0, n-1);
        Mergesort(0, n-1);
        if (m == 0)
        {
            for (int i = 0; i < n - 1; i++)
            {
                cout << a[i] << " ";
            }
            cout << a[n - 1] << endl;
        }
        else{
            for (int i = n - 1; i > 0; i--)
            {
                cout << a[i] << " ";
            }
            cout << a[0] << endl;
        }
    }
    

    return 0;
}