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  1. #include <iostream>
  2. using namespace std;
  3.  
  4. struct segtree {
  5.     int lb, rb;
  6.     int sum = 0;
  7.     segtree *l = 0, *r = 0;
  8.     segtree (int _lb, int _rb) {
  9.         lb = _lb, rb = _rb;
  10.     }
  11.     void extend () {
  12.         int t = (lb + rb) / 2;
  13.         if (!l) {
  14.             l = new segtree(lb, t);
  15.             r = new segtree(t+1, rb);
  16.         }
  17.     }
  18.     void add (int k, int x) {
  19.         sum += x;
  20.         if (lb != rb) {
  21.             extend();
  22.             int t = (lb + rb) / 2;
  23.             if (k <= t) l->add(k, x);
  24.             else r->add(k, x);
  25.         }
  26.     }
  27.     int get_sum (int lq, int rq) {
  28.         if (lb >= lq && rb <= rq) return sum;
  29.         if (lb > rq || rb < lq) return 0;
  30.         extend();
  31.         return l->get_sum(lq, rq) + r->get_sum(lq, rq);
  32.     }
  33. };
  34. int main() {
  35.     int n;
  36.     cin >> n;
  37.     int ans = 0;
  38.     segtree tree(0, 1e9);
  39.     const int k = 1e9 / n / 2;
  40.     for (int i = 0; i < n; ++i) {
  41.         ans += tree.get_sum(k * i, k * i + 1e9 / 2);
  42.     }
  43.     cout << ans << endl;
  44.     return 0;
  45. }
  46.  
  47.  
  48.  
Success #stdin #stdout 0.36s 424272KB
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stdin 
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https://ideone.com/idLyz6
language:
C++14 (gcc 8.3)
created:
6 years ago
visibility:
public

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