Submission #229701

#	Time	Username	Problem	Language	Result	Execution time	Memory
229701		Nightlight	Palembang Bridges (APIO15_bridge)	C++14	0 / 100	13 ms	15232 KiB

bridge

#include <queue>
#include <cstdio>
#include <cstring>
#include <set>
#define pii pair<int, int>
#define piii tuple<int, int, int>
#define mt make_tuple
#define push_back emplace_back
using namespace std;
 
int N, M;
int pos, mov, sta, fin;
vector<pii> adj[30005];
set<int> here[300005];
int dist[30005];

void BFS() {
  memset(dist, 0x3f3f3f3f, sizeof(dist));
  priority_queue<pii, vector<pii>, greater<pii>> pq;
  pq.push(make_pair(0, sta));
  dist[sta] = 0;
  while(!pq.empty()) {
    int u = pq.top().second;
    int now = pq.top().first;
    pq.pop();
    if(dist[u] < now) continue;
    for(pii v : adj[u]) {
      if(dist[u] + v.second < dist[v.first]) {
        dist[v.first] = dist[u] + v.second;
        pq.push(make_pair(dist[v.first], v.first));
      }
    }
  }
  if(dist[fin] == 0x3f3f3f3f) puts("-1");
  else printf("%d\n", dist[fin]);
}
 
int main() {
  scanf("%d %d", &N, &M);
  scanf("%d %d", &pos, &mov);
  here[pos].insert(mov);
  sta = pos;
  scanf("%d %d", &pos, &mov);
  here[pos].insert(mov);
  fin = pos;
  for(int i = 2; i < M; i++) {
    scanf("%d %d", &pos, &mov);
    here[pos].insert(mov);
  }
  for(int i = 0; i <= N; i++) {
    if(i == fin) continue;
    for(int now : here[i]) {
      for(int nxt = i - now, p = 1; nxt >= 0; nxt -= now, p++) {
        adj[i].push_back(nxt, p);
        if(here[nxt].count(p)) break;
      }
      for(int nxt = i + now, p = 1; nxt <= N; nxt += now, p++) {
        adj[i].push_back(nxt, p);
        if(here[nxt].count(p)) break;
      }
    }
  }
  BFS();
}

Compilation message (stderr)

bridge.cpp: In function 'int main()':
bridge.cpp:39:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d %d", &N, &M);
   ~~~~~^~~~~~~~~~~~~~~~~
bridge.cpp:40:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d %d", &pos, &mov);
   ~~~~~^~~~~~~~~~~~~~~~~~~~~
bridge.cpp:43:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d %d", &pos, &mov);
   ~~~~~^~~~~~~~~~~~~~~~~~~~~
bridge.cpp:47:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d %d", &pos, &mov);
     ~~~~~^~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 8
• Subtask 2: 0 / 14
• Subtask 3: 0 / 9
• Subtask 4: 0 / 32
• Subtask 5: 0 / 37