Submission #41574748

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Source Code Expand

#include<bits/stdc++.h>
#define ff first
#define ss second
#define all(vs) vs.begin(), vs.end()

using namespace std;
using pii = pair<int, int>;
using ll = long long;
using pll = pair<ll, ll>;
using ld = long double;

using vvi = vector<vector<ll>>;
using vi = vector<ll>;
using vpi = vector<pair<ll, ll>>;

const ll oo = 1e18;
const ll maxn = 5 * 1e5 + 100;
const double PI = acos(-1);


int solve(){
    int n, m, ans = 0;
    cin >> n >> m;
    vector<set<int>> vs(n);
    vector<vector<int>> ts(m+1);
    set<int> st;

    for (int j=0; j<n; j++){
        int a;
        cin >> a;

        for (int i=0; i<a; i++){
            int x;
            cin >> x;
            vs[j].insert(x);
            ts[x].push_back(j);
        }
    }

    bitset<maxn> vis(0);
    priority_queue<pair<int, int>, vector<pair<int, int>>, greater<pair<int, int>>> q;

    for (auto x: ts[1]) {
        q.emplace(0, x);
        vis[x] = 1;
    }
    while(!q.empty()){
        auto [d, st] = q.top();
        q.pop();

        if (vs[st].count(m)) return d;

        for (auto num: vs[st]){
            for (auto to: ts[num]){
                if (!vis[to]){
                    vis[to] = 1;
                    q.emplace(d+1, to);
                }
            }
        }
    }

    return -1;
}


int main(){
    int tt=1;

    while(tt--){
        cout << solve() << endl;
    }
}

Submission Info

Compile Error

./Main.cpp: In function ‘int solve()’:
./Main.cpp:22:15: warning: unused variable ‘ans’ [-Wunused-variable]
   22 |     int n, m, ans = 0;
      |               ^~~

Judge Result