归并排序

#include<bits/stdc++.h>
using namespace std;
int n;


void mergearray(int a[], int l, int mid, int r, int temp[]) {
    int i = l, j = mid + 1;
    int m = mid, n = r;
    int k = 0;
    while(i <= m && j <= n) {
        if(a[i] <= a[j]) {
            temp[k++] = a[i++];
        }
        else {
            temp[k++] = a[j++];
        }
    }
    while(i <= m) {
        temp[k++] = a[i++];
    }
    while(j <= n) {
        temp[k++] = a[j++];
    }
    for(i = 0; i < k; i++) {
        a[l++] = temp[i];
    }
}

void mergesort(int a[], int l, int r, int temp[]) {
    if(l < r) {
        int mid = (l + r) >> 1;
        mergesort(a, l, mid, temp);
        mergesort(a, mid + 1, r, temp);
        mergearray(a, l, mid, r, temp);
    }
}

int main() {
    cin >> n;
    ans = 0;
    int arr[10005], temp[10005];
    for(int i = 0; i < n; i++) {
        cin >> arr[i];
    }
    mergesort(arr, 0, n - 1, temp);
    for(int i = 0; i < n; i++) {
        cout << arr[i] << " ";
    }cout << endl;
    return 0;
}