Submission #991899

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Source Code Expand

#include<cstdio>
#include<algorithm>

using namespace std;

struct UnionFind{
	int par[200200];
	void init(int N){
		for(int i = 0; i < N; ++i) par[i] = i;
	}
	int find(int x){
		if(x == par[x]) return x;
		return par[x] = find(par[x]);
	}
	void unite(int x, int y){
		x = find(x);
		y = find(y);
		par[x] = y;
	}
	bool same(int x, int y){
		return find(x) == find(y);
	}
};

UnionFind uf;

int main(){
	int N;
	scanf("%d", &N);
	int M;
	scanf("%d", &M);
	uf.init(N + M);
	for(int i = 0; i < N; ++i){
		int k;
		scanf("%d", &k);
		for(int j = 0; j < k; ++j){
			int l;
			scanf("%d", &l);
			uf.unite(i, l + N - 1);
		}
	}
	for(int i = 0; i < N; ++i){
		if(!uf.same(0, i)){
			printf("NO\n");
			return 0;
		}
	}
	printf("YES\n");
	return 0;
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:29:17: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d", &N);
                 ^
./Main.cpp:31:17: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d", &M);
                 ^
./Main.cpp:35:18: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d", &k);
                  ^
./Main.cpp:38:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
    scanf("%d", &l);
                   ^

Judge Result