제출 #527374

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
527374		79brue	From Hacks to Snitches (BOI21_watchmen)	C++14	15 / 100	6079 ms	241920 KiB

watchmen

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;

struct dat{
    int x, f, y;
    int nxt=0;
    dat(){}
    dat(int x, int f, int y): x(x), f(f), y(y){}

    bool operator<(const dat &r)const{
        return y>r.y;
    }
};

int n, m, k;
vector<int> link[250002];
int cycleLen[250002];
int cycleIdx[250002];
vector<int> dist[250002];
vector<bool> visited[250002];
queue<dat> pq;
dat datList[10000000];
int datSize = 3;

void update(dat tmp){
    if(tmp.x){
        if(visited[tmp.x][tmp.f]) return;
        visited[tmp.x][tmp.f] = 1;
        dist[tmp.x][tmp.f] = tmp.y;
    }
    pq.push(tmp);
}

int main(){
    scanf("%d %d", &n, &m);
    for(int i=1; i<=m; i++){
        int x, y;
        scanf("%d %d", &x, &y);
        link[x].push_back(y);
        link[y].push_back(x);
    }

    scanf("%d", &k);
    while(k--){
        int l;
        scanf("%d", &l);
        for(int j=0; j<l; j++){
            int tmp;
            scanf("%d", &tmp);
            cycleLen[tmp] = l;
            cycleIdx[tmp] = j;
        }
    }

    for(int i=1; i<=n; i++){
        if(!cycleLen[i]) cycleLen[i] = 1;
        dist[i] = vector<int> (cycleLen[i], 1e9);
        visited[i].resize(cycleLen[i]);
    }

    update(dat(1, 0, 0));

    int pqCnt = 0;
    while(!pq.empty()){
        dat tmp = pq.front(); pq.pop();
        int x = tmp.x, f = tmp.f, y = tmp.y;
//        printf("%d %d: %d\n", x, f, y);
//        assert(f < cycleLen[x]);

        if(tmp.nxt){
            pq.push(datList[tmp.nxt]);
        }
        if(tmp.x == 0) continue;

        if(x==n){
            printf("%d", y);
            return 0;
        }

        if(cycleLen[x] == 1){
            for(int nxt: link[x]){
                if(cycleLen[nxt] == 1) update(dat(nxt, 0, y+1));
                else{
                    if(visited[nxt][0] || visited[nxt][1] || visited[nxt][2]) continue;
                    int prv = 0;
                    for(int j=cycleLen[nxt]-1; j>=0; j--){
                        int nf = (y+1+j)%cycleLen[nxt];
                        if(nf == cycleIdx[nxt]){
                            datList[datSize++] = dat(0, 0, y+j+1);
                            datList[datSize-1].nxt = prv;
                            prv = datSize-1;
                        }
                        else{
                            datList[datSize++] = (dat(nxt, nf, y+j+1));
                            datList[datSize-1].nxt = prv;
                            prv = datSize-1;
                            visited[tmp.x][tmp.f] = 1;
                            dist[tmp.x][tmp.f] = tmp.y;
                        }
                    }
                    update(datList[datSize-1]);
                }
            }
        }
        else{
            for(int nxt: link[x]){
                if(cycleLen[nxt] == 1) update(dat(nxt, 0, y+1));
                else{
                    int nf = (f+1)%cycleLen[nxt];
                    if(nf == cycleIdx[nxt]) continue;
                    if(nf == cycleIdx[x] && f%cycleLen[nxt] == cycleIdx[nxt]) continue;
                    update(dat(nxt, nf, y+1));
                }
            }
        }
    }

    printf("impossible");
}

컴파일 시 표준 에러 (stderr) 메시지

watchmen.cpp: In function 'int main()':
watchmen.cpp:66:9: warning: unused variable 'pqCnt' [-Wunused-variable]
   66 |     int pqCnt = 0;
      |         ^~~~~
watchmen.cpp:38:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   38 |     scanf("%d %d", &n, &m);
      |     ~~~~~^~~~~~~~~~~~~~~~~
watchmen.cpp:41:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   41 |         scanf("%d %d", &x, &y);
      |         ~~~~~^~~~~~~~~~~~~~~~~
watchmen.cpp:46:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   46 |     scanf("%d", &k);
      |     ~~~~~^~~~~~~~~~
watchmen.cpp:49:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   49 |         scanf("%d", &l);
      |         ~~~~~^~~~~~~~~~
watchmen.cpp:52:18: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   52 |             scanf("%d", &tmp);
      |             ~~~~~^~~~~~~~~~~~

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