제출 #892526

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
892526		MilosMilutinovic	Bulldozer (JOI17_bulldozer)	C++14	100 / 100	996 ms	35652 KiB

bulldozer

#include <bits/stdc++.h>
 
using namespace std;
 
struct pt {
  int x, y;
};
 
bool same(int x1, int y1, int x2, int y2) {
  // y1 / x1 = y2 / x2
  return x1 * 1LL * y2 == y1 * 1LL * x2;
}

long long cross(pt a, pt b) {
  return a.x * 1LL * b.y - a.y * 1LL * b.x;
}

int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int n;
  cin >> n;
  vector<int> x(n), y(n), w(n);
  for (int i = 0; i < n; i++) {
    cin >> x[i] >> y[i] >> w[i];
  }
  vector<int> order(n);
  iota(order.begin(), order.end(), 0);
  sort(order.begin(), order.end(), [&](int i, int j) {
    if (y[i] != y[j]) {
      return y[i] < y[j];
    } else {
      return x[i] < x[j];
    }
  });
  vector<int> pos(n);
  for (int i = 0; i < n; i++) {
    pos[order[i]] = i;
  }
  vector<long long> mx(4 * n);
  vector<long long> sum(4 * n);
  vector<long long> pref(4 * n);
  vector<long long> suff(4 * n);
  auto Pull = [&](int x) {
    sum[x] = sum[x << 1] + sum[x << 1 | 1];
    mx[x] = max({mx[x << 1], mx[x << 1 | 1], suff[x << 1] + pref[x << 1 | 1]});
    pref[x] = max(pref[x << 1], sum[x << 1] + pref[x << 1 | 1]);
    suff[x] = max(suff[x << 1 | 1], sum[x << 1 | 1] + suff[x << 1]);
  };
  function<void(int, int, int)> Build = [&](int x, int l, int r) {
    if (l == r) {
      sum[x] = w[order[l]];
      mx[x] = max(0LL, sum[x]);
      pref[x] = max(0LL, sum[x]);
      suff[x] = max(0LL, sum[x]);
      return;
    }
    int mid = l + r >> 1;
    Build(x << 1, l, mid);
    Build(x << 1 | 1, mid + 1, r);
    Pull(x);
  };
  function<void(int, int, int, int)> Update = [&](int x, int l, int r, int p) {
    if (l == r) {
      sum[x] = w[order[l]];
      mx[x] = max(0LL, sum[x]);
      pref[x] = max(0LL, sum[x]);
      suff[x] = max(0LL, sum[x]);
      return;
    }
    int mid = l + r >> 1;
    if (p <= mid) {
      Update(x << 1, l, mid, p);
    } else {
      Update(x << 1 | 1, mid + 1, r, p);
    }
    Pull(x);
  };
  Build(1, 0, n - 1);
  vector<array<int, 4>> qs;
  for (int _i = 0; _i < n; _i++) {
    for (int _j = _i + 1; _j < n; _j++) {
      int i = order[_i];
      int j = order[_j];
      int fx = x[j] - x[i];
      int fy = y[j] - y[i];
      if (fy < 0 || (fy == 0 && fx < 0)) {
        fx = -fx;
        fy = -fy;
      }
      qs.push_back({fx, fy, i, j});
    }
  }
  sort(qs.begin(), qs.end(), [&](array<int, 4> a, array<int, 4> b) {
    pt p;
    p.x = a[0];
    p.y = a[1];
    pt q;
    q.x = b[0];
    q.y = b[1];
    if (cross(p, q) == 0) {
      return make_pair(pos[a[2]], pos[a[3]]) < make_pair(pos[b[2]], pos[b[3]]);
    }
    return cross(p, q) > 0;
  });
  int sz = (int) qs.size();
  long long ans = mx[1];
  for (int i = 0; i < sz; i++) {
    int ptr = i;
    while (ptr < sz && same(qs[i][0], qs[i][1], qs[ptr][0], qs[ptr][1])) {
      swap(order[pos[qs[ptr][2]]], order[pos[qs[ptr][3]]]);
      swap(pos[qs[ptr][2]], pos[qs[ptr][3]]);
      Update(1, 0, n - 1, pos[qs[ptr][2]]);
      Update(1, 0, n - 1, pos[qs[ptr][3]]);
      ptr += 1;
    }
    ans = max(ans, mx[1]);
    i = ptr - 1;
  }
  cout << ans << '\n';
  return 0;
}

컴파일 시 표준 에러 (stderr) 메시지

bulldozer.cpp: In lambda function:
bulldozer.cpp:58:17: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   58 |     int mid = l + r >> 1;
      |               ~~^~~
bulldozer.cpp: In lambda function:
bulldozer.cpp:71:17: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   71 |     int mid = l + r >> 1;
      |               ~~^~~

• Subtask 1: 5 / 5
• Subtask 2: 20 / 20
• Subtask 3: 35 / 35
• Subtask 4: 20 / 20
• Subtask 5: 20 / 20