Submission #1093893

#	Time	Username	Problem	Language	Result	Execution time	Memory
1093893		Wjsc	Joker (BOI20_joker)	C++14	6 / 100	22 ms	9044 KiB

Joker

#include<bits/stdc++.h>

using namespace std;

#define pi pair<int, int>
#define fi first
#define se second
#define all(v) v.begin(), v.end()

const int N = 2e5 + 5;

int n, m, q;
pi edge[N];
vector<int> ad[N];

namespace sub1 {
  bool ok = 0;
  int col[N];

  void dfs(int u, int c) {
    col[u] = c;
    for(auto v : ad[u]) {
      if(col[v] == col[u]) ok = 1;
      if(col[v] == -1) dfs(v, c ^ 1);
    }
  }

  void solve() {
    while(q--) {
      int l, r; cin >> l >> r;

      for(int i = 1; i <= n; ++i) ad[i].clear();

      for(int i = 1; i < l; ++i) {
        int u, v; tie(u, v) = edge[i];
        ad[u].push_back(v);
        ad[v].push_back(u);
      }
      for(int i = r + 1; i <= m; ++i) {
        int u, v; tie(u, v) = edge[i];
        ad[u].push_back(v);
        ad[v].push_back(u);
      }

      for(int i = 1; i <= n; ++i) col[i] = -1;

      ok = 0;
      for(int i = 1; i <= n; ++i)
        if(col[i] == -1) dfs(i, 0);

      cout << (ok ? "YES\n" : "NO\n");
    }
  }
}

signed main() {
  cin.tie(0)->sync_with_stdio(0);

  if(fopen("task.inp", "r")) {
    freopen("task.inp", "r", stdin);
    freopen("task.out", "w", stdout);
  }

  cin >> n >> m >> q;

  for(int i = 1; i <= m; ++i) {
    int u, v; cin >> u >> v;
    edge[i] = {u, v};
  }

  if(n <= 200 && m <= 200 && q <= 200) sub1 :: solve();
}

Compilation message (stderr)

Joker.cpp: In function 'int main()':
Joker.cpp:60:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   60 |     freopen("task.inp", "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
Joker.cpp:61:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   61 |     freopen("task.out", "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 6 / 6
• Subtask 2: 0 / 8
• Subtask 3: 0 / 25
• Subtask 4: 0 / 10
• Subtask 5: 0 / 22
• Subtask 6: 0 / 29