Submission #404523

#	Time	Username	Problem	Language	Result	Execution time	Memory
404523		doowey	From Hacks to Snitches (BOI21_watchmen)	C++14	0 / 100	108 ms	38468 KiB

watchmen

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef pair<int, int> pii;

#define fi first
#define se second
#define mp make_pair
#define fastIO ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);

const int N = 250110;
const int inf = (int)1e9;
vector<int> T[N];
int id[N];
int mod[N];
int ash[N];
vector<int> ord[N];
vector<int> dp[N];
vector<bool> vis[N];

struct item{
    int dist;
    int node;
    int inv;
    bool operator<(const item &q) const {
        return dist > q.dist;
    }
};

int main(){
    fastIO;
    int n, m;
    cin >> n >> m;
    int ui, vi;
    for(int i = 1; i <= m; i ++ ){
        cin >> ui >> vi;
        T[ui].push_back(vi);
        T[vi].push_back(ui);
    }
    int k;
    cin >> k;
    int sz;
    for(int iq = 1; iq <= k ; iq ++ ){
        cin >> sz;
        for(int j = 0; j < sz; j ++ ){
            cin >> ui;
            ash[ui] = j;
            mod[ui] = sz;
            id[ui] = iq;
            ord[iq].push_back(ui);
        }
    }
    for(int i = 1; i <= n; i ++ ){
        if(id[i] == 0){
            vis[i].resize(1, false);
            dp[i].resize(1, inf);
        }
        else{
            vis[i].resize(mod[i], false);
            dp[i].resize(mod[i], inf);
        }
    }
    priority_queue<item> pq;
    dp[1][0] = 0;
    pq.push({0, 1, 0});
    int node;
    int iinv;
    int dis;
    int ban0, ban1;
    int nex;
    while(!pq.empty()){
        dis = pq.top().dist;
        node = pq.top().node;
        iinv = pq.top().inv;
        pq.pop();
        if(vis[node][iinv]) continue;
        vis[node][iinv] = true;
        if(id[node] == 0){
            for(auto x : T[node]){
                if(id[x] == 0){
                    if(dp[x][0] > dis + 1){
                        dp[x][0] = dis + 1;
                        pq.push({dp[x][0], x, 0});
                    }
                }
                else{
                    for(int wait = 1; wait <= mod[x]; wait ++ ){
                        if(ord[id[x]][(wait + dis) % mod[x]] != x && dp[x][(wait + dis) % mod[x]] > dis + wait){
                            dp[x][(wait + dis) % mod[x]] = dis + wait;
                            pq.push({dp[x][(wait + dis) % mod[x]], x, (wait + dis) % mod[x]});
                        }
                    }
                }

            }
        }
        else{
            for(auto x : T[node]){
                if(id[x] == 0){
                    if(dp[x][0] > dis + 1){
                        dp[x][0] = dis + 1;
                        pq.push({dp[x][0], x, 0});
                    }
                }
                else if(id[x] == id[node]){
                    if((ash[x] + 1) % mod[x] != ash[node] && ord[id[x]][(dis + 1) % mod[x]] != x){
                        if(dp[x][(dis + 1) % mod[x]] > dis + 1){
                            dp[x][(dis + 1) % mod[x]] = dis + 1;
                            pq.push({dis + 1, x, (dis + 1) % mod[x]});
                        }
                    }
                }

            }

            ban0 = ord[id[node]][iinv];
            ban1 = ord[id[node]][(iinv + 1 + mod[node]) % mod[node]];

            nex = ord[id[node]][(ash[node] + 1) % mod[node]];
            if(dp[nex][(iinv + 1) % mod[nex]] > dis + 1){
                dp[nex][(iinv + 1) % mod[nex]] = dis + 1;
                pq.push({dis + 1, nex, (iinv + 1) % mod[nex]});
            }
            nex = ord[id[node]][(ash[node] - 1 + mod[node]) % mod[node]];
            if(dp[nex][(iinv + 1) % mod[nex]] > dis + 1){
                dp[nex][(iinv + 1) % mod[nex]] = dis + 1;
                pq.push({dis + 1, nex, (iinv + 1) % mod[nex]});
            }

        }
    }
    if(dp[n][0] < inf)
        cout << dp[n][0] << "\n";
    else
        cout << "impossible\n";
    return 0;
}

Compilation message (stderr)

watchmen.cpp: In function 'int main()':
watchmen.cpp:71:9: warning: variable 'ban0' set but not used [-Wunused-but-set-variable]
   71 |     int ban0, ban1;
      |         ^~~~
watchmen.cpp:71:15: warning: variable 'ban1' set but not used [-Wunused-but-set-variable]
   71 |     int ban0, ban1;
      |               ^~~~

• 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