基础算法--快排，归并排序

#include<iostream>
#include<cstdio>
using namespace std;
const int N=1e6+10;
int n;
int q[N];
void quick_sort(int q[],int l,int r){
    if(l>=r){
        return ;
    }
    int x=q[l+r>>1],i=l-1,j=r+1;
    while(i<j){
        do i++; while(q[i]<x);
        do j--; while(q[j]>x);
        if(i<j){
            swap(q[i],q[j]);
        }
    }
    quick_sort(q,l,j);
    quick_sort(q,j+1,r);
}
int main(void){
    scanf("%d",&n);
    for(int i=0;i<n;i++){
        scanf("%d",&q[i]);
    }
    quick_sort(q,0,n-1);
    for(int i=0;i<n;i++){
        printf("%d ",q[i]);
    }
    return 0;
}

#include<iostream>
#include<cstdio>
using namespace std;
const int N=1e6+10;
int n;
int q[N];
int tmp[N];
void merge_sort(int q[],int l,int r){
    if(l>=r){
        return ;
    }
    int mid = l+r>>1;
    merge_sort(q,l,mid);
    merge_sort(q,mid+1,r);
    int k=0;
    int i=l,j=mid+1;
    while(i<=mid&&j<=r){
        if(q[i]<q[j])
            tmp[k++]=q[i++];
        else
            tmp[k++]=q[j++];
    }
    while(i<=mid)
        tmp[k++]=q[i++];
    while(j<=r)
        tmp[k++]=q[j++];
    for(i=l,j=0;i<=r;i++,j++)
        q[i]=tmp[j];
}
int main (void){
    scanf("%d",&n);
    for(int i=0;i<n;i++){
        scanf("%d",&q[i]);
    }
    merge_sort(q,0,n-1);
    for(int i=0;i<n;i++){
        printf("%d ",q[i]);
    }
    return 0;
}