Submission #1093645

#TimeUsernameProblemLanguageResultExecution timeMemory
1093645duyhoanhoJoker (BOI20_joker)C++17
0 / 100
2058 ms8472 KiB
#include<bits/stdc++.h> #define int long long #define forinc(i,a,b) for(int i=a;i<=b;i++) #define fi first #define se second #define pii pair<int,int> #define pb push_back using namespace std; const int N = 2e5+10; int n,m,p[N],sz[N],lz[N],q; pii ad[N]; int pa(int v,int &c) { c ^= lz[v]; if(p[v] == v) return v; return pa(p[v] , c); } void join(int a,int b) { int ca = 0; int cb = 0; a = pa(a,ca); b = pa(b,cb); if(a != b) { if(sz[a] < sz[b]) swap(a,b); sz[a] += sz[b]; p[b] = a; if(ca == cb) lz[b] = 1; } } bool check(int a,int b) { int ca = 0; int cb = 0; a = pa(a,ca); b = pa(b,cb); if(a == b && ca == cb) return true; return false; } bool qu(int l,int r) { forinc(i,1,n) { sz[i] = 1; p[i] = i; } for(int i=1;i<=m;i++) { if(l<=i && i<=r) continue; if(check(ad[i].fi , ad[i].se)) return true; join(ad[i].fi , ad[i].se); } return false; } int32_t main() { if(fopen("task.inp","r")) { freopen("task.inp","r",stdin); freopen("task.out","w",stdout); } ios_base::sync_with_stdio(false); cin.tie(0); cin>>n>>m>>q; forinc(i,1,m) { int x,y; cin>>x>>y; ad[i] = {x,y}; } while(q--) { int l,r; cin>>l>>r; cout<< (qu(l,r) ? "YES\n" : "NO\n"); } }

Compilation message (stderr)

Joker.cpp: In function 'int32_t main()':
Joker.cpp:60:16: 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:61:16: 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);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
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