Submission #37680

#	Time	Username	Problem	Language	Result	Execution time	Memory
37680		funcsr	Bulldozer (JOI17_bulldozer)	C++14	5 / 100	6 ms	1024 KiB

bulldozer

#include <cstdio>
#include <iostream>
#include <algorithm>
#include <string>
#include <cstring>
#include <vector>
#include <queue>
#include <set>
#include <map>
#include <cmath>
#include <iomanip>
#include <cassert>
#include <bitset>
using namespace std;

typedef pair<int, int> P;
typedef pair<P, int> P2;
#define rep(i, n) for (int i=0; i<(n); i++)
#define all(c) (c).begin(), (c).end()
#define uniq(c) c.erase(unique(all(c)), (c).end())
#define index(xs, x) (int)(lower_bound(all(xs), x) - xs.begin())
#define _1 first
#define _2 second
#define pb push_back
#define INF 1145141919
#define MOD 1000000007
struct Node {
  long long s, l, r, m;
  Node(long long s, long long l, long long r, long long m) : s(s), l(l), r(r), m(m) {}
  Node(long long w) : Node(w, max(w, 0LL), max(w, 0LL), max(w, 0LL)) {}
  Node() : Node(0) {}
};
Node op(const Node &a, const Node &b) {
  return Node(
    a.s + b.s,
    max(a.l, a.s + b.l),
    max(b.r, b.s + a.r),
    max(max(a.m, b.m), a.r + b.l)
  );
}

#define MAX_N (1<<11)
Node seg[MAX_N*2-1];
void update(int k, Node x) {
  k += MAX_N-1;
  seg[k] = x;
  while (k > 0) {
    k = (k-1)/2;
    seg[k] = op(seg[k*2+1], seg[k*2+2]);
  }
}

int N;
int X[2000], Y[2000], W[2000];
int gcd(int x, int y) {
  if (x > y) swap(x, y);
  if (x == 0) return y;
  return gcd(y%x, x);
}

struct Rel {
  int p, q;
  Rel(int p, int q) : p(p), q(q) {
    if (q < 0) p = -p, q = -q;
    //int g = gcd(abs(p), abs(q)); p/=g, q/=g;
  }
  bool operator<(const Rel& b) const {
    return p*b.q < b.p*q;
  }
};
map<Rel, vector<P> > lines;
int pos[2000];

signed main() {
  ios::sync_with_stdio(false); cin.tie(0);
  cin >> N;
  vector<P2> ps;
  rep(i, N) {
    int x, y, w;
    cin >> x >> y >> w;
    ps.pb(P2(P(x, -y), w));
  }
  sort(all(ps));
  rep(i, N) X[i] = ps[i]._1._1, Y[i] = -ps[i]._1._2, W[i] = ps[i]._2, pos[i] = i, update(i, Node(W[i]));
  rep(i, N) rep(j, i) {
    Rel r = Rel(-1, 0);
    if (X[i] != X[j]) r = Rel(Y[i]-Y[j], X[i]-X[j]);
    lines[r].pb(P(i, j));
  }
  long long m = seg[0].m;
  for (auto &p : lines) {
    //rep(i, N)cout<<seg[i+MAX_N-1].s<<",";cout<<": "<<seg[0].m<<"\n";
    Rel a = p._1;
    map<long long, vector<P>> bs;
    auto add = [&](int i) {
      int x = X[i], y = Y[i];
      bs[1LL*y*a.q-1LL*x*a.p].pb(P(pos[i], i));
    };
    for (P p : p._2) add(p._1), add(p._2);
    for (auto &p : bs) {
      vector<P> &ps = p._2;
      sort(all(ps)); uniq(ps);
      rep(i, ps.size()/2) {
        int a = ps[i]._2, b = ps[(int)ps.size()-1-i]._2;
        swap(pos[a], pos[b]);
        update(pos[a], Node(W[a]));
        update(pos[b], Node(W[b]));
      }
    }
    m = max(m, seg[0].m);
  }
  cout << m << "\n";
  return 0;
}

Compilation message (stderr)

bulldozer.cpp: In function 'int main()':
bulldozer.cpp:18:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
 #define rep(i, n) for (int i=0; i<(n); i++)
                                  ^
bulldozer.cpp:103:7: note: in expansion of macro 'rep'
       rep(i, ps.size()/2) {
       ^~~

• Subtask 1: 5 / 5
• Subtask 2: 0 / 20
• Subtask 3: 0 / 35
• Subtask 4: 0 / 20
• Subtask 5: 0 / 20