Submission #1012378

#TimeUsernameProblemLanguageResultExecution timeMemory
1012378simona1230Star Trek (CEOI20_startrek)C++17
Compilation error
0 ms0 KiB
#include <bits/stdc++.h> using namespace std; const int mod=1e9+7; int n,d; vector<int> v[100001]; void read() { cin>>n>>d; for(int i=1;i<n;i++) { int x,y; cin>>x>>y; v[x].push_back(y); v[y].push_back(x); } } int num; int l[100001],w[100001]; void dfs1(int i,int p) { for(int j=0;j<v[i].size();j++) { int nb=v[i][j]; if(nb==p)continue; dfs1(nb,i); l[i]+=w[nb]^1; } if(l[i])w[i]=1; } int c[100001],sz[100001],up[100001]; void dfs2(int i,int p) { if(i!=1&&w[p]==0||w[p]==1&&l[p]==1&&!w[i])w[i]+=2; //cout<<i<<" "<<w[i]<<endl; if(w[i]==0)num++; for(int j=0;j<v[i].size();j++) { int nb=v[i][j]; if(nb==p)continue; dfs2(nb,i); if(l[i]==1&&w[nb]!=1||l[i]==0) sz[i]+=sz[nb]; } if(w[i]%2==0)sz[i]++; //cout<<i<<" "<<sz[i]<<endl; } void dfs3(int i,int p) { int add=up[p]+sz[p]; if(l[p]==1&&w[i]!=1||i!=1&&l[p]==0) add-=sz[i]; up[i]=add; c[i]=add+sz[i]; for(int j=0;j<v[i].size();j++) { int nb=v[i][j]; if(nb==p)continue; dfs3(nb,i); } } int main() { ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL); read(); dfs1(1,0); dfs2(1,0); dfs3(1,0); if(!w[i])cout<<(sz[1]*num)%mod<<endl; else cout<<(mod+n*n-(sz[1]*num)%mod)%mod<<endl; return 0; }

Compilation message (stderr)

startrek.cpp: In function 'void dfs1(int, int)':
startrek.cpp:24:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   24 |     for(int j=0;j<v[i].size();j++)
      |                 ~^~~~~~~~~~~~
startrek.cpp: In function 'void dfs2(int, int)':
startrek.cpp:38:12: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
   38 |     if(i!=1&&w[p]==0||w[p]==1&&l[p]==1&&!w[i])w[i]+=2;
      |        ~~~~^~~~~~~~~
startrek.cpp:42:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   42 |     for(int j=0;j<v[i].size();j++)
      |                 ~^~~~~~~~~~~~
startrek.cpp:47:19: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
   47 |         if(l[i]==1&&w[nb]!=1||l[i]==0)
      |            ~~~~~~~^~~~~~~~~~
startrek.cpp: In function 'void dfs3(int, int)':
startrek.cpp:57:15: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
   57 |     if(l[p]==1&&w[i]!=1||i!=1&&l[p]==0)
      |        ~~~~~~~^~~~~~~~~
startrek.cpp:62:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   62 |     for(int j=0;j<v[i].size();j++)
      |                 ~^~~~~~~~~~~~
startrek.cpp: In function 'int main()':
startrek.cpp:80:8: error: 'i' was not declared in this scope
   80 |  if(!w[i])cout<<(sz[1]*num)%mod<<endl;
      |        ^