AcWing 787. 归并排序
原题链接
简单
#include<iostream>
using namespace std;
const int N =100010;
int q[N],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 i = l,j=mid+1,k=0;
while(i<=mid && j <= r)
{
if(q[i]<=q[j]) tmp[k++]=q[i++];
if(q[i]>q[j]) tmp[k++]=q[j++];
}
while(i<=mid) tmp[k++]=q[i++];
while(j <=r) tmp[k++] = q[j++];
for(int i =l,j=0;i<=r;i++,j++) q[i]=tmp[j];
}
int main(){
int n;
cin >> 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;
}