Submission #992801

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Source Code Expand

#include <cstdio>
#include <cstring>
#include <vector>

using namespace std;

vector<int> g[200000];
bool v[200000] = {};

void rec(int i)
{
    v[i] = true;
    for (int j = 0; j < g[i].size(); ++j)
        if (!v[g[i][j]])
            rec(g[i][j]);
}

int main()
{
    int n, m;
    scanf("%d %d", &n, &m);

    for (int i = 0; i < m; ++i)
        v[100000 + i] = true;

    for (int i = 0; i < n; ++i) {
        int k;
        scanf("%d", &k);

        for (int j = 0; j < k; ++j) {
            int l;
            scanf("%d", &l);
            l -= 1;
            g[i].push_back(100000 + l);
            g[100000 + l].push_back(i);
            v[100000 + l] = false;
        }
    }

    rec(0);

    bool ans = true;
    for (int i = 0; i < n; ++i)
        ans = ans && v[i];
    for (int i = 0; i < m; ++i)
        ans = ans && v[100000 + i];
    if (ans)
        printf("YES\n");
    else
        printf("NO\n");

    return 0;
}

Submission Info

Judge Result