제출 #538938

#제출 시각아이디문제언어결과실행 시간메모리
538938Soul234Network (BOI15_net)C++14
0 / 100
1 ms212 KiB
#include<bits/stdc++.h> using namespace std; void DBG() { cerr << "]\n"; } template<class H, class... T> void DBG(H h, T... t) { cerr << h; if(sizeof...(t)) cerr << ", "; DBG(t...); } #ifdef LOCAL #define dbg(...) cerr << "[" << #__VA_ARGS__ << "]: [", DBG(__VA_ARGS__) #else #define dbg(...) 0 #endif // LOCAL #define FOR(i,a,b) for(int i = (a) ; i<(b) ; i++) #define F0R(i,a) FOR(i,0,a) #define ROF(i,a,b) for(int i = (b)-1 ; i>=(a) ; i--) #define R0F(i,a) ROF(i,0,a) #define each(e,a) for(auto &e : (a)) #define sz(v) (int)(v).size() #define all(v) (v).begin(),(v).end() #define rall(v) (v).rbegin(),(v).rend() #define pb push_back #define tcT template<class T #define nl "\n" using ll = long long; using vi = vector<int>; using pi = pair<int,int>; using str = string; tcT> using V = vector<T>; tcT> using pqg = priority_queue<T,vector<T>,greater<T>>; void setIO(string NAME = "") { cin.tie(0)->sync_with_stdio(0); if(sz(NAME)) { freopen((NAME + ".inp").c_str(),"r",stdin); freopen((NAME + ".out").c_str(),"w",stdout); } } const int MX = 5e5+5; int N, deg[MX]; void solve() { cin>>N; F0R(i,N-1) { int u,v; cin>>u>>v; deg[u]++; deg[v]++; } vi lfs; FOR(i,1,N+1) if(deg[i] == 1) lfs.pb(i); int SZ = (sz(lfs)+1)/2; cout << (sz(lfs)+1)/2 << nl; F0R(i,sz(lfs)/2) { cout << lfs[i] << " " << lfs[i+SZ] << nl; } if(sz(lfs)&1) cout << 1 << " " << lfs[sz(lfs)/2] << nl; } int main() { setIO(); int t=1; //cin>>t; while(t-->0) { solve(); } return 0; }

컴파일 시 표준 에러 (stderr) 메시지

net.cpp: In function 'void setIO(std::string)':
net.cpp:37:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   37 |         freopen((NAME + ".inp").c_str(),"r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
net.cpp:38:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   38 |         freopen((NAME + ".out").c_str(),"w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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