算法模板
1.排序
(1)快速排序(No STL)
#include <bits/stdc++.h>
using namespace std;
#define int long long
int n,a[100010];
void dfs(int l,int r)
{
if(l >= r)
return ;
int pos = (l + r) >> 1;
int x = a[pos];
int i = l,j = r;
while(i <= j)
{
while(a[i] < x)
i++;
while(a[j] > x)
j--;
if(i <= j)
swap(a[i],a[j]),i++,j--;
}
dfs(l,j);
dfs(i,r);
}
signed main()
{
cin >> n;
for(int i = 1; i <= n; i++)
cin >> a[i];
dfs(1,n);
for(int i = 1; i <= n; i++)
cout << a[i] << " ";
cout << "\n";
return 0;
}