Submission #1186861

#TimeUsernameProblemLanguageResultExecution timeMemory
1186861hainam2k9Graph (BOI20_graph)C++20
0 / 100
1 ms2632 KiB
#include <bits/stdc++.h> #define tt cin.tie(0), cout.tie(0), ios_base::sync_with_stdio(0) #define fo freopen((NAME+".INP").c_str(), "r", stdin), freopen((NAME+".OUT").c_str(), "w", stdout) #define ll long long #define ull unsigned long long #define i128 __int128 #define db long double #define sz(a) ((int)(a).size()) #define pb emplace_back #define pf emplace_front #define pob pop_back #define pof pop_front #define lb lower_bound #define ub upper_bound #define fi first #define se second #define ins emplace #define mp make_pair using namespace std; const int MOD = 1e9+7, MAXN = 1e5+5; const string NAME = ""; int n,m,depth[MAXN],par[MAXN]; ll sum[MAXN]; db rs[MAXN]; bool vis[MAXN],ok[MAXN],vis2[MAXN]; vector<pair<int,int>> adj[MAXN],v; map<pair<int,int>,int> MP; inline bool diff(db& a, db b){ return abs(a-b)>1e-6; } pair<int,db> dfs(int u, int parent, int sgn){ vis[u]=1; for(pair<int,int>& e : adj[u]){ if(e.fi==parent) continue; if(vis[e.fi]){ if((depth[u]-depth[e.fi]+1)&1){ if(sgn) return {e.fi,(sum[u]-sum[par[e.fi]]+e.se)/2.0}; return {e.fi,(sum[par[e.fi]]-sum[u]+e.se)/2.0}; } if(sum[u]-sum[par[e.fi]]!=0) cout << "NO", exit(0); }else{ depth[e.fi]=depth[u]+1, par[e.fi]=u, sum[e.fi]=sum[u]+sgn*e.se; pair<int,db> p = dfs(e.fi,u,-sgn); if(p.fi>0) return p; } } return {0,0}; } void dfs2(int u, db sum, int sgn, vector<pair<int,db>>& v){ vis2[u]=1; for(pair<int,int>& e : adj[u]) if(!vis2[e.fi]) v.pb(e.fi,sum+sgn*e.se), dfs2(e.fi,sum+sgn*e.se,-sgn,v); } void Answer(int u, db val){ if(ok[u]&&diff(rs[u],val)) cout << "NO", exit(0); ok[u]=1, rs[u]=val; queue<pair<int,db>> q; q.ins(u,val); while(!q.empty()){ pair<int,db> p=q.front(); q.pop(); for(pair<int,int>& e : adj[p.fi]){ if(!ok[e.fi]) ok[e.fi]=1, rs[e.fi]=e.se-p.se, q.ins(e.fi,rs[e.fi]); else if(diff(rs[e.fi],e.se-p.se)) cout << "NO", exit(0); } } } int main() { tt; if(fopen((NAME + ".INP").c_str(), "r")) fo; cout << fixed << setprecision(7); cin >> n >> m; for(int i = 1; i<=m; ++i){ int x,y,z; cin >> x >> y >> z; if(MP[{x,y}]==0){ MP[{x,y}]=MP[{y,x}]=z, adj[x].pb(y,z), adj[y].pb(x,z); if(x==y) v.pb(x,z); }else if(MP[{x,y}]!=z) cout << "NO", exit(0); } for(pair<int,int>& p : v) Answer(p.fi,p.se); for(int i = 1; i<=n; ++i) if(!ok[i]){ pair<int,db> val=dfs(i,0,1); if(val.fi==0){ vector<pair<int,db>> v; dfs2(i,0,1,v); if(!v.empty()) sort(v.begin(),v.end()), val=v[sz(v)>>1]; } Answer(val.fi,val.se); } cout << "YES\n"; for(int i = 1; i<=n; ++i) cout << rs[i] << " "; }

Compilation message (stderr)

Graph.cpp: In function 'int main()':
Graph.cpp:3:19: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
    3 | #define fo freopen((NAME+".INP").c_str(), "r", stdin), freopen((NAME+".OUT").c_str(), "w", stdout)
      |            ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Graph.cpp:71:45: note: in expansion of macro 'fo'
   71 |     if(fopen((NAME + ".INP").c_str(), "r")) fo;
      |                                             ^~
Graph.cpp:3:63: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
    3 | #define fo freopen((NAME+".INP").c_str(), "r", stdin), freopen((NAME+".OUT").c_str(), "w", stdout)
      |                                                        ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Graph.cpp:71:45: note: in expansion of macro 'fo'
   71 |     if(fopen((NAME + ".INP").c_str(), "r")) fo;
      |                                             ^~
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