Submission #991633

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Source Code Expand

#include <cstdio>
#include <algorithm>
#include <vector>
#include <stack>
#include <queue>
#include <set>
#include <map>
#include <cstring>
#include <string>
#include <cmath>
#include <cstdlib>
#include <iostream>

using namespace std;

#define MOD @
#define ADD(X,Y) ((X) = ((X) + (Y)) % MOD)
typedef long long i64; typedef vector<int> ivec; typedef vector<string> svec;

int N, M;
vector<int> L[101010];

int uf[303030];

int root(int p)
{
	return uf[p] < 0 ? p : (uf[p] = root(uf[p]));
}
void join(int p, int q)
{
	p = root(p);
	q = root(q);
	if (p == q) return;
	uf[p] += uf[q];
	uf[q] = p;
}

int main()
{
	scanf("%d%d", &N, &M);
	for (int i = 0; i < N; ++i) {
		int k;
		scanf("%d", &k);
		for (; k--;) {
			int v;
			scanf("%d", &v);
			--v;
			L[i].push_back(v);
		}
	}
	for (int i = 0; i < N + M; ++i) uf[i] = -1;
	for (int i = 0; i < N; ++i) {
		for (int l : L[i]) {
			join(i, l + N);
		}
	}
	int rt = root(0);
	for (int i = 1; i < N; ++i) {
		if (rt != root(i)) {
			puts("NO");
			return 0;
		}
	}
	puts("YES");
	return 0;
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:40:23: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d", &N, &M);
                       ^
./Main.cpp:43:18: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d", &k);
                  ^
./Main.cpp:46:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
    scanf("%d", &v);
                   ^

Judge Result