Submission #134958

#TimeUsernameProblemLanguageResultExecution timeMemory
134958ly20Beads and wires (APIO14_beads)C++17
0 / 100
11 ms10360 KiB
#include<bits/stdc++.h> using namespace std; const int MAXN=212345; vector<int> grafo[MAXN],peso[MAXN]; int dp[MAXN][5],marc[MAXN]; void dfs(int v,int p) { marc[v]=1; if(v!=0 && grafo[v].size()==1) { dp[v][0]=0;dp[v][1]=p;dp[v][2]=0; return; } int d1=-1123456,d2=-1123456,tot=0; for(int i=0;i<grafo[v].size();i++) { int viz=grafo[v][i],ps=peso[v][i]; if(marc[viz]==1)continue; dfs(viz,ps); if(dp[viz][1]-max(dp[viz][0],dp[viz][2])>d1)d1=dp[viz][1]-max(dp[viz][0],dp[viz][2]); if(d1>d2)swap(d1,d2); tot+=max(dp[viz][0],dp[viz][2]); } dp[v][0]=max(tot+d1+d2,tot); dp[v][2]=tot+d2+p; dp[v][1]=max(tot+d1+d2+p,tot+p); } int main() { int n; scanf("%d",&n); for(int i=0;i<n-1;i++) { int a,b,p; scanf("%d %d %d",&a,&b,&p);a--;b--; grafo[a].push_back(b);grafo[b].push_back(a); peso[a].push_back(p);peso[b].push_back(p); } dfs(0,0); printf("%d\n",dp[0][0]); /*for(int i=0;i<n;i++) { printf("%d %d %d %d\n",i,dp[i][0],dp[i][1],dp[i][2]); }*/ return 0; }

Compilation message (stderr)

beads.cpp: In function 'void dfs(int, int)':
beads.cpp:15:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<grafo[v].size();i++)
              ~^~~~~~~~~~~~~~~~
beads.cpp: In function 'int main()':
beads.cpp:31:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d",&n);
  ~~~~~^~~~~~~~~
beads.cpp:35:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d %d %d",&a,&b,&p);a--;b--;
   ~~~~~^~~~~~~~~~~~~~~~~~~~~
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