Submission #853686

#	Time	Username	Problem	Language	Result	Execution time	Memory
853686		NeroZein	Jakarta Skyscrapers (APIO15_skyscraper)	C++17	0 / 100	1 ms	1116 KiB

skyscraper

#include "bits/stdc++.h"
using namespace std;

#ifdef Nero
#include "Deb.h"
#else
#define deb(...)
#endif

const int N = 30004;

int seen[N];
vector<int> in[N];

int main(){
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  int n, m;
  cin >> n >> m;
  for (int i = 0; i < m; ++i) {
    int v, p;
    cin >> v >> p;
    in[v].push_back(p); 
  }
  fill(seen, seen + N, -1); 
  set<pair<int, int>> vis; 
  priority_queue<array<int, 3>> pq; 
  for (int p : in[0]) {
    pq.push({0, p, 0}); 
    vis.emplace(p, 0);
  }
  seen[0] = 0;
  while (!pq.empty()) {
    auto [c, p, v] = pq.top();
    c = -c; 
    //deb(p) deb(c) deb(v) cout << endl;
    //assert(v >= 0);
    pq.pop();
    int forward = v + p;
    if (forward < n && !vis.count({p, forward})) {
      if (seen[forward] == -1) {
        seen[forward] = c + 1; 
        for (int np : in[forward]) {
          vis.emplace(np, forward); 
          pq.push({-(c + 1), np, forward}); 
        }
      }
      vis.emplace(p, forward); 
      pq.push({-(c + 1), p, forward}); 
    }
    int backward = v - p;
    if (backward >= 0 && !vis.count({p, backward})) {
      if (seen[backward] == -1) {
        seen[backward] = c + 1; 
        for (int np : in[backward]) {
          vis.emplace(np, backward); 
          pq.push({-(c + 1), np, backward}); 
        }
      }
      vis.emplace(p, backward); 
      pq.push({-(c + 1), p, backward}); 
    }
  }
  cout << seen[1] << '\n';
  return 0;
}

• Subtask 1: 0 / 10
• Subtask 2: 0 / 12
• Subtask 3: 0 / 14
• Subtask 4: 0 / 21
• Subtask 5: 0 / 43