Submission #457936

#	Time	Username	Problem	Language	Result	Execution time	Memory
457936		elgamalsalman	Jakarta Skyscrapers (APIO15_skyscraper)	C++14	57 / 100	1088 ms	2696 KiB

skyscraper

#pragma GCC optimize("Ofast")

#include <bits/stdc++.h>

using namespace std;

#define fi first
#define se second
#define ww first
#define vv second

typedef long long ll;
typedef pair<ll, ll> llll;
typedef pair<int, int> ii;
typedef pair<int, ii> iii;
typedef vector<int> vi;
typedef vector<ii> vii;
typedef vector<vi> vvi;
typedef vector<vii> vvii;

int N, M, b[30'050], p[30'050];
ll sssp[30'050];
vvi dogesAt;
bitset<30'050> visited;

void bfs() {
  memset(sssp, -1, sizeof sssp);
  queue<iii> q;
  for (int doge : dogesAt[b[0]]) {
    sssp[doge] = 0;
    visited[doge] = 1;
    if (doge == 1) return;
    q.push({b[0], {p[doge], 0}});
    q.push({b[0], {-p[doge], 0}});
  }
  while (!q.empty()) {
    iii u = q.front(); q.pop();
    //cerr << "// {" << u.fi << ", {" << u.se.fi << ", " << u.se.se << "}}\n";
    int newPos = u.fi + u.se.fi;
    if (newPos >= 0 && newPos < N) {
      q.push({newPos, {u.se.fi, u.se.se + 1}});
      for (int doge : dogesAt[newPos]) if (!visited[doge]) {
	sssp[doge] = u.se.se + 1;
	visited[doge] = 1;
	if (doge == 1) return;
	q.push({newPos, {p[doge], u.se.se + 1}});
	q.push({newPos, {-p[doge], u.se.se + 1}});
      }
    }
  }
}

int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);

  cin >> N >> M;
  dogesAt.assign(N + 20, vi());
  for (int i = 0; i < M; i++) {
    cin >> b[i] >> p[i];
    dogesAt[b[i]].push_back(i);
  }
  
  bfs();

  //cerr << "// sssp :";
  //for (int i = 0; i < M; i++) cerr << ' ' << sssp[i];
  //cerr << '\n';

  cout << sssp[1] << '\n';
}

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