Submission #651884

#	Time	Username	Problem	Language	Result	Execution time	Memory
651884		pauloamed	Jakarta Skyscrapers (APIO15_skyscraper)	C++14	57 / 100	472 ms	262144 KiB

skyscraper

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

const int MAXN = 30010;


vector<int> col2i[MAXN];
vector<int> ans[MAXN];

int ps[MAXN];

int x2j(int id, int x){
  int p = ps[id];
  return x / p;
}

int& ans_at(int i, int x){
  if(i == -1)
    return ans[i + 1][x];
  else
    return ans[i + 1][x2j(i, x)];
}

int32_t main(){
  cin.tie(NULL)->sync_with_stdio(false);

  int n, m; cin >> n >> m;

  int B[2], P[2];
  cin >> B[0] >> P[0];
  cin >> B[1] >> P[1];

  vector<pair<int,int>> v;
  for(int i = 2; i < m; ++i){
    int b, p; cin >> b >> p;
    v.push_back({p, b});
  }
  sort(v.begin(), v.end());
  v.erase(unique(v.begin(), v.end()), v.end());

  ans[0] = vector<int>(n, INT_MAX);
  for(int i = 0; i < v.size(); ++i){
    auto [p, b] = v[i];
    ps[i] = p;

    for(int j = b % p; j < n; j += p){
      ans[i+1].push_back(INT_MAX);
    }
    col2i[b].push_back(i);
  }
  v.clear();

  struct Node{
    int i, x;
    // se i == -1, eh col
    int cost;
    bool operator<(const Node &n) const{
      return cost > n.cost;
    }
  };

  priority_queue<Node> pq;
  deque<Node> q;
  for(int i = (B[0] % P[0]); i < n; i += P[0]){
    int dist = abs(i - B[0]) / P[0];
    pq.push({-1, i, ans_at(-1, i) = dist});
  }

  // print();

  while(pq.size() + q.size() > 0){
    auto maybe_update = [&](int p, int x, int val, int d){
      if(ans_at(p, x) > val){
        Node X = {p, x, ans_at(p, x) = val};
        
        if(d == 0) q.push_front(X);
        else if(d == 1) q.push_back(X);
        else pq.push(X);
      }
    };


    Node nxt;
    {
      if(q.size()){
        nxt = q.front();
        q.pop_front();
      }else{
        nxt = pq.top(); pq.pop();
      }
    }
    auto [i, x, cost] = nxt;
    if(cost > ans_at(i, x)) continue;

    // cout << i << " " << x << " " << cost << "\n";

    if(i == -1){
      for(auto i : col2i[x]){
        maybe_update(i, x, cost, 0);
      }
    }else{
      // sou power i na coluna x
      maybe_update(-1, x, cost, 0);

      if(x + ps[i] < n){
        maybe_update(i, x + ps[i], cost + 1, 1);
      }

      if(x - ps[i] >= 0){
        maybe_update(i, x - ps[i], cost + 1, 1);
      }
    }

    // print();
  }

  cout << ((ans_at(-1, B[1]) == INT_MAX)? -1 : ans_at(-1, B[1])) << "\n";
}

Compilation message (stderr)

skyscraper.cpp: In function 'int32_t main()':
skyscraper.cpp:42:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   42 |   for(int i = 0; i < v.size(); ++i){
      |                  ~~^~~~~~~~~~
skyscraper.cpp:43:10: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   43 |     auto [p, b] = v[i];
      |          ^
skyscraper.cpp:92:10: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   92 |     auto [i, x, cost] = nxt;
      |          ^

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