0分求助

LLEeeeEe @ 2024-02-12 15:44:47

#include<iostream>
#include<algorithm>
using namespace std;
int main()
{
    int n,m,i,a[500000],b=0;
    scanf("%d",&n);
    cin>>m;
      for(i=0;i<n;i++)
      cin>>a[i];
      sort(a,a+n);
      for(i=0;i<n;i++)
      {
       if(a[i]!=a[i+1])
       b++;
       if(b==m)
       cout<<a[i+1]<<endl;
       break;
    }

    system("pause");
}

by cabbage_flower @ 2024-02-12 15:48:17

@LLEeeeEe 呃，数据范围是500万，你写的是50万

by shtian @ 2024-02-12 15:56:43

@LLEeeeEe 代码O(n * n),可以重写了

by shtian @ 2024-02-12 15:59:43

建议使用nth_element，O（n）

#include <bits/stdc++.h>
using namespace std;
int x[5000005], k;

int main() {
    int n;
    scanf("%d%d", &n, &k);
    for (int i = 0; i < n; i++)
        scanf("%d", &x[i]);
    nth_element(x, x + k, x + n);
    printf("%d", x[k]);
}