func_code_string: #include <bits/stdc++.h>   using namespace std;   const int N = 3010;   int n;   int x[N], y[N], top;   pair<int, pair<int, int> > st[N * N];   bitset<N> adj[N];   int sqr(int u) { return u * u; }   int main() {     scanf( %d , &n);     for (int i = 1; i <= n; i++) {       scanf( %d %d , &x[i], &y[i]);     }     for (int i = 1; i <= n; i++) {       for (int j = i + 1; j <= n; j++) {         int dis = sqr(abs(x[i] - x[j])) + sqr(abs(y[i] - y[j]));         st[top++] = make_pair(dis, make_pair(i, j));       }     }     sort(st, st + top);     for (int i = top - 1; i >= 0; i--) {       int dis = st[i].first;       int a = st[i].second.first;       int b = st[i].second.second;       if ((adj[a] & adj[b]).any()) {         printf( %0.17f , sqrt(dis) / 2);         return 0;       }       adj[a][b] = 1;       adj[b][a] = 1;     }     return 0;   }   