王道快速排序和归并排序的完整代码

这是快排的代码要作为模板背下来

#include<iostream>
#include<algorithm>
using namespace std;
int poration(int *a,int low,int high)//用来每次找最中间的那个元素(分割元素)
{
    int mid=a[low];
    while(low<high)
    {
        while(low<high&&a[high]>=mid) high--;
        a[low]=a[high];
        while(low<high&&a[low]<=mid) low++;
        a[high]=a[low];
    }
    a[low]=mid;
    return low;
}
void quicksort(int *a,int low,int high)//主要进行递归的函数，用来进行快速排序，quicksort
{
    if(low<high)
    {
        int mid=poration(a,low,high);
        quicksort(a,low,mid-1);
        quicksort(a,mid+1,high);
    }
}
int main()
{
    int n;
    cin>>n;
    int a[n];
    for(int i=0;i<n;i++)
    cin>>a[i];
    quicksort(a,0,n-1);
    for(int j=0;j<n;j++)
    cout<<a[j]<<" ";
}

这是归并的模板都来自王道书上

#include<iostream>
#include<algorithm>
using namespace std;
int b[100];//用来存放数字的数字，用来返回较小值
void merge(int *a,int low,int mid,int high)
{
    for(int i=low;i<=high;i++)
    b[i]=a[i];
    int i=low,k=low,j=mid+1;//这里面的东西写道下面的for循环之中也是可以的
    for(;i<=mid&&j<=high;k++)//for(int i=low,int k=low,int j=mid+1;i<=mid&&j<=high;k++)
    {
        if(b[i]<b[j])
        a[k]=b[i++];
        else
        a[k]=b[j++];
    }
    while(i<=mid) a[k++]=b[i++];
    while(j<=high) a[k++]=b[j++];
}
void mergelist(int *a,int low,int high)
{
    if(low<high)
    {
        int mid=(low+high)/2;
        mergelist(a,low,mid);
        mergelist(a,mid+1,high);
        merge(a,low,mid,high);
    }
}
int main()
{
    int n;
    cin>>n;
    int a[n];
    for(int i=0;i<n;i++)
    cin>>a[i];
    mergelist(a,0,n-1);
    for(int i=0;i<n;i++)
    cout<<a[i]<<" ";
}