Submission #425933

#	Time	Username	Problem	Language	Result	Execution time	Memory
425933		duality	From Hacks to Snitches (BOI21_watchmen)	C++11	0 / 100	109 ms	10044 KiB

watchmen

#include <bits/stdc++.h>
using namespace std;
#define mp make_pair
#define pb push_back
typedef long long int LLI;
typedef vector<int> vi;
typedef pair<int,int> pii;
typedef vector<pii> vpii;

vi adjList[250000];
pair<int,pii> p[250000];
int dist[250000];
priority_queue<pii> H;
int main() {
    int i,j;
    int N,M,K;
    int u,v,l;
    scanf("%d %d",&N,&M);
    for (i = 0; i < M; i++) {
        scanf("%d %d",&u,&v);
        u--,v--;
        adjList[u].pb(v);
        adjList[v].pb(u);
    }
    scanf("%d",&K);
    for (i = 0; i < K; i++) {
        scanf("%d",&l);
        for (j = 0; j < l; j++) scanf("%d",&v),p[v-1] = mp(l,mp(j,i));
    }

    for (i = 0; i < N; i++) dist[i] = -1;
    dist[0] = 0,H.push(mp(0,0));
    while (!H.empty()) {
        int u = H.top().second;
        int d = -H.top().first;
        H.pop();

        if (d > dist[u]+2) continue;
        for (i = 0; i < adjList[u].size(); i++) {
            int v = adjList[u][i];
            if (p[v].first != 0) {
                if (((d+1) % p[v].first) == p[v].second.first) continue;
                if (((d % p[v].first) == p[v].second.first) && (p[u].second.second == p[v].second.second) \
                    && (p[u].second.first == ((p[v].second.first+1) % p[v].first))) continue;
            }
            if ((dist[v] == -1) || (d+1 < dist[v])) {
                dist[v] = d+1;
                H.push(mp(-dist[v],v));
            }
        }
        d++;
        if ((p[u].first != 0) && ((d % p[u].first) == p[u].second.first)) continue;
        H.push(mp(-d,u));
    }
    if (dist[N-1] == -1) printf("impossible\n");
    else printf("%d\n",dist[N-1]);

    return 0;
}

Compilation message (stderr)

watchmen.cpp: In function 'int main()':
watchmen.cpp:39:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   39 |         for (i = 0; i < adjList[u].size(); i++) {
      |                     ~~^~~~~~~~~~~~~~~~~~~
watchmen.cpp:18:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   18 |     scanf("%d %d",&N,&M);
      |     ~~~~~^~~~~~~~~~~~~~~
watchmen.cpp:20:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   20 |         scanf("%d %d",&u,&v);
      |         ~~~~~^~~~~~~~~~~~~~~
watchmen.cpp:25:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   25 |     scanf("%d",&K);
      |     ~~~~~^~~~~~~~~
watchmen.cpp:27:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   27 |         scanf("%d",&l);
      |         ~~~~~^~~~~~~~~
watchmen.cpp:28:38: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   28 |         for (j = 0; j < l; j++) scanf("%d",&v),p[v-1] = mp(l,mp(j,i));
      |                                 ~~~~~^~~~~~~~~

• Subtask 1: 0 / 5
• Subtask 2: 0 / 10
• Subtask 3: 0 / 10
• Subtask 4: 0 / 10
• Subtask 5: 0 / 25
• Subtask 6: 0 / 20
• Subtask 7: 0 / 20