Acwing785.快速排序
Acwing785.快速排序
快排模板:
y总教学大法好~:
#include <iostream>
using namespace std;
const int N = 1000010;
int q[N];
void quick_sort(int q[], int l, int r)
{
if (l >= r) return;
int i = l - 1, j = r + 1, x = q[l + 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()
{
int n;
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;
}
C++ STL快速算法:
#include <bits/stdc++.h>
using namespace std;
const int N=1000000+100;
int a[N],n,m,i,j;
int main()//C++ Stl使人快乐
{
ios::sync_with_stdio(false);
cin>>n;
for(int i=1;i<=n;i++)
cin>>a[i];
sort(a+1,a+1+n);
for(int i=1;i<=n;i++)
cout<<a[i]<<" ";
cout<<endl;
}
Acwing原题链接(https://www.acwing.com/problem/content/787/)
785.快速排序(链接同上)
练习题
偷懒写法:
#include<iostream>
#include<algorithm>
using namespace std;
const int MAXN = 1e6+10;
long long int num[MAXN];
int n,k;
int main(){
cin>>n>>k;
for(int i =0 ;i< n ;i++)
{
scanf("%d",&num[i]);
}
sort(num,num+n);
cout<<num[k-1];
}
y总大法好~:
(小声bb:完全套模板,都不用思考的)
#include<iostream>
#include<algorithm>
using namespace std;
const int MAXN = 1e6+10;
long long int num[MAXN];
int n,k;
void quick_sort(long long int q[],int l,int r)
{
if(l>=r)return ;
int i = l - 1, j = r + 1, x = q[l + 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(){
cin>>n>>k;
for(int i =0 ;i< n ;i++)
{
scanf("%d",&num[i]);
}
quick_sort(num,0,n-1);
cout<<num[k-1];
}