基础算法（二）归并排序模板
模板如下
#include<iostream> using namespace std; const int N=1000010; int q[N],tmp[N]; void merge_sort(int q[],int l,int r){ if(l>=r)return; int mid = (l+r)>>1; int k=0,i=l,j=mid+1; merge_sort(q,l,mid); merge_sort(q,mid+1,r); 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(int i=l,j=0;i<=r;i++,j++)q[i]=tmp[j]; } int main(){ int n; scanf("%d",&n); for(int i =0;i<n;i++)scanf("%d",&q[i]); merge_sort(q,0,n-1); for(int j=0;j<n;j++)cout<<q[j]<<" "; return 0; }