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最新推荐文章于 2025-12-09 11:28:31 发布

原创最新推荐文章于 2025-12-09 11:28:31 发布 · 156 阅读

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#c++ #算法 #数据结构

#include<cstdio>
#include<iostream>
#include<algorithm>
using namespace std;

int n,m;
int const N = 50005;
int q[N];

bool check(int mid){
   int cnt = 0;
   for(int i = 0; i < n;i++){
       int tmp = mid + q[i];
       int pos = upper_bound(q,q+n,tmp) - q;
       cnt += n - pos;
   }
   return cnt <= m;
}

int main(){
   while(scanf("%d",&n) != EOF){
       m = (n * (n - 1)) / 4;
       for(int i = 0;i < n;i++){
           scanf("%d",&q[i]);
       }
       sort(q,q+n);
       int l = 0,r = q[n-1] - q[0];
       while(l < r){
           int mid = (l + r) >> 1;
           if(check(mid)) r = mid;
           else l = mid + 1;
       }
       cout << l << endl;
   }

return 0;
}