Submission #1336576

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Source Code Expand

#define _USE_MATH_DEFINES
#include <cassert>
#include <cstdio>
#include <cstring>
#include <iostream>
#include <string>
#include <sstream>
#include <vector>
#include <queue>
#include <stack>
#include <list>
#include <set>
#include <map>
#include <unordered_set>
#include <unordered_map>
#include <algorithm>
#include <complex>
#include <cmath>
#include <numeric>
#include <bitset>

using namespace std;

#define trace(...) __f(#__VA_ARGS__, __VA_ARGS__)
template <typename Arg1>
void __f(const char* name, Arg1&& arg1){
  cerr << name << ": " << arg1 << endl;
}
template <typename Arg1, typename... Args>
void __f(const char* names, Arg1&& arg1, Args&&... args){
  const char* comma = strchr(names + 1, ',');
  cerr.write(names, comma - names) << ": " << arg1 << " |";
  __f(comma + 1, args...);
}

typedef long long int64;
typedef pair<int, int> ii;
const int INF = 1 << 30;
const int MOD = 1e9 + 7;

const int N = 1e5 + 10;
vector<int> a[N];
int f[N];

int find(int x) {
  if (f[x] != f[f[x]]) f[x] = find(f[x]);
  return f[x];
}

int main() {
  int n, m;
  scanf("%d%d", &n, &m);
  for (int i = 0; i < n; ++i) {
    int len;
    scanf("%d", &len);
    while (len--) {
      int x;
      scanf("%d", &x);
      --x;
      a[x].push_back(i);
    }
    f[i] = i;
  }
  for (int i = 0; i < m; ++i) {
    for (int j = 1; j < a[i].size(); ++j) {
      int x = a[i][j - 1], y = a[i][j];
      int rx = find(x), ry = find(y);
      if (rx != ry) {
        f[ry] = rx;
      }
    }
  }
  int ret = 0;
  for (int i = 0; i < n; ++i) {
    if (find(i) == i) ++ret;
  }
  puts(ret == 1 ? "YES" : "NO");
  return 0;
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:52:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d%d", &n, &m);
                        ^
./Main.cpp:55:22: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d", &len);
                      ^
./Main.cpp:58:22: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
       scanf("%d", &x);
                      ^

Judge Result