Submission #991793

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Source Code Expand

#include <algorithm>
#include <cstdio>
#include <functional>
#include <iostream>
#include <cfloat>
#include <climits>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <map>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <time.h>
#include <vector>
using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> i_i;
typedef pair<ll, int> ll_i;
typedef pair<double, int> d_i;
typedef pair<ll, ll> ll_ll;
typedef pair<double, double> d_d;
struct edge { int u, v; ll w; };

#define rep(i, N) for (int i = 0; i < N; i++)
#define pb push_back

ll MOD = 1000000007;
ll _MOD = 1000000009;
double EPS = 1e-10;

struct union_find {
	vector<int> v;
	union_find(int n) : v(n, -1) {}
	int find(int x) { return v[x] < 0 ? x : v[x] = find(v[x]); }
	void unite(int x, int y) {
		x = find(x); y = find(y);
		if (x == y) return;
		if (-v[x] < -v[y]) swap(x, y);
		v[x] += v[y]; v[y] = x;
	}
	bool root(int x) { return v[x] < 0; }
	bool same(int x, int y) { return find(x) == find(y); }
	int size(int x) { return -v[find(x)]; }
};

int main() {
	int N, M; cin >> N >> M;
	vector<vector<int> > a(N);
	rep(i, N) {
		int K; scanf("%d", &K);
		while (K--) {
			int x; scanf("%d", &x);
			a[i].pb(x);
		}
	}
	vector<int> A;
	rep(i, N) for (int x: a[i]) A.pb(x);
	sort(A.begin(), A.end());
	A.erase(unique(A.begin(), A.end()), A.end());
	M = A.size();
	rep(i, N) for (int& x: a[i]) x = lower_bound(A.begin(), A.end(), x) - A.begin();
	union_find uf(N + M);
	rep(i, N) for (int x: a[i]) uf.unite(i, N + x);
	cout << (uf.size(0) == N + M ? "YES" : "NO") << endl;
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:55:25: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
   int K; scanf("%d", &K);
                         ^
./Main.cpp:57:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
    int x; scanf("%d", &x);
                          ^

Judge Result