제출 #979131

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
979131		MilosMilutinovic	Lightning Rod (NOI18_lightningrod)	C++14	66 / 100	2075 ms	262144 KiB

Main

#include <bits/stdc++.h>

using namespace std;

template <typename T>
class fenwick {
 public:
  vector<T> fenw;
  int n;

  fenwick(int _n) : n(_n) {
    fenw.resize(n);
  }

  void modify(int x, T v) {
    while (x < n) {
      fenw[x] += v;
      x |= (x + 1);
    }
  }

  T get(int x) {
    T v{};
    while (x >= 0) {
      v += fenw[x];
      x = (x & (x + 1)) - 1;
    }
    return v;
  }
};

int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int n;
  cin >> n;
  vector<int> x(n);
  vector<int> y(n);
  for (int i = 0; i < n; i++) {
    int a, b;
    cin >> a >> b;
    x[i] = a - b;
    y[i] = a + b;
  }
  vector<int> order(n);
  iota(order.begin(), order.end(), 0);
  sort(order.begin(), order.end(), [&](int i, int j) {
    if (x[i] != x[j]) {
      return x[i] < x[j];
    } else {
      return y[i] > y[j];
    }
  });
  auto xs = y;
  sort(xs.begin(), xs.end());
  xs.erase(unique(xs.begin(), xs.end()), xs.end());
  fenwick<int> fenw(n + 1);
  int ans = 0;
  for (int i : order) {
    int v = (int) (lower_bound(xs.begin(), xs.end(), y[i]) - xs.begin());
    if (fenw.get(n - v) == 0) {
      ans += 1;
      fenw.modify(n - v, +1);
    }
  }
  cout << ans << '\n';
  return 0;
}

• Subtask 1: 0 / 4
• Subtask 2: 7 / 7
• Subtask 3: 12 / 12
• Subtask 4: 21 / 21
• Subtask 5: 26 / 26
• Subtask 6: 0 / 10
• Subtask 7: 0 / 20