全TLE，能不能优化一下算法

xffdeg @ 2024-08-27 20:04:49

#include <iostream>
using namespace std;
int ans = 0 , k;
void findkth(int a[] , int l , int r){
    if(l == r){
        ans = a[l];
        return;
    }
    int i = l , j = r , flag = a[(l + r) / 2] , tmp;
    do{
        while(a[i] < flag) i++;
        while(a[j] > flag) j--;
        if(i <= j){
            tmp = a[i];
            a[i] = a[j];
            a[j] = tmp;
            i++;
            j--;
        }
    }while(i <= j);
    if(k <= j)findkth(a, l, j);
    else if(k <= i)findkth(a, i, r);
    else findkth(a , j + 1 , i - 1);
}
int main (){
    int n;
    cin >> n >> k;
    int a[n];
    for(int i = 0;i < n;i++)
        cin >> a[i];
    findkth(a, 0, n - 1);
    cout << ans << endl;
    return 0;
}

by chenhaihang @ 2024-08-27 20:13:33

#include<bits/stdc++.h>
using namespace std;
int n,m,a[5000001];
int main()
{
    std::ios::sync_with_stdio(false);//写了就只能用cincout但会更快
    cin>>n>>m;
    for(int i=0;i<n;i++)
    {
        cin>>a[i];
    }
    sort(a+0,a+n);快速排序
    cout<<a[m];
    return 0;
 }

@xffdeg

by xffdeg @ 2024-08-27 20:13:33

@dream_dad 能具体列一下吗

by Yxy7952 @ 2024-08-27 20:13:51

@xffdeg

如果只是单纯为了AC，代码如下，侥幸能过

#include<bits/stdc++.h>
using namespace std;
int n,k,a[5000005];
int main(){
    scanf("%d%d",&n,&k);
    for(int i=1;i<=n;i++){
        scanf("%d",&a[i]);
    }
    sort(a+1,a+n+1);
    printf("%d",a[k+1]);
    return 0;
}

by xffdeg @ 2024-08-27 20:14:47

@chenhaihang 以关注谢谢指导

by Yxy7952 @ 2024-08-27 20:14:48

@xffdeg

但是这道题的初衷设计不是这样的，楼主可以看一下题解

by xffdeg @ 2024-08-27 20:15:20

@yixingyou 以关注谢谢指导