Submission #289340

#TimeUsernameProblemLanguageResultExecution timeMemory
289340TadijaSebezCapital City (JOI20_capital_city)C++11
100 / 100
1140 ms66296 KiB
#include <bits/stdc++.h> using namespace std; #define pb push_back #define pii pair<int,int> const int N=200050; const int L=18; int up[N],lca[N],c[N]; int Find(int x){return up[x]==x?x:up[x]=Find(up[x]);} vector<int> nodes[N],E[N]; int par[N][L],dep[N],head[N],lid[N],rid[N],sz[N],tme; void Tree(int u,int p){ par[u][0]=p; dep[u]=dep[p]+1; sz[u]=1; for(int i=1;i<L;i++)par[u][i]=par[par[u][i-1]][i-1]; for(int v:E[u])if(v!=p)Tree(v,u),sz[u]+=sz[v]; } void HLD(int u,int p){ if(!head[u])head[u]=u; lid[u]=++tme; int hc=0; for(int v:E[u])if(v!=p&&(!hc||sz[hc]<sz[v]))hc=v; if(hc)head[hc]=head[u],HLD(hc,u); for(int v:E[u])if(v!=p&&v!=hc)HLD(v,u); rid[u]=tme; } int LCA(int u,int v){ if(dep[u]<dep[v])swap(u,v); for(int i=L-1;~i;i--)if(dep[par[u][i]]>=dep[v])u=par[u][i]; for(int i=L-1;~i;i--)if(par[u][i]!=par[v][i])u=par[u][i],v=par[v][i]; return u==v?v:par[v][0]; } const int M=2*N; pii st[M]; pii operator + (pii a,pii b){return {min(a.first,b.first),a.second+b.second};} int ls[M],rs[M],tsz,root; void Set(int&c,int ss,int se,int qi,pii x){ if(!c)c=++tsz; if(ss==se){st[c]=x;return;} int mid=ss+se>>1; if(qi<=mid)Set(ls[c],ss,mid,qi,x); else Set(rs[c],mid+1,se,qi,x); st[c]=st[ls[c]]+st[rs[c]]; } pii Get(int c,int ss,int se,int qs,int qe){ if(qs>qe||ss>qe||qs>se)return {N,0}; if(qs<=ss&&qe>=se)return st[c]; int mid=ss+se>>1; return Get(ls[c],ss,mid,qs,qe)+Get(rs[c],mid+1,se,qs,qe); } void Rem(int i){for(int j:nodes[i])up[j]=par[j][0];} int ptr[N]; int Get(int col){ while(ptr[col]<nodes[col].size()&&dep[Find(nodes[col][ptr[col]])]<dep[lca[col]])ptr[col]++; if(ptr[col]==nodes[col].size())return 0; else return c[Find(nodes[col][ptr[col]])]; } int disc[N],low[N],tid,ans; stack<int> stk; bool in[N],has_out[N]; int val[N]; void AddHLD(int col){ for(int i:nodes[col])Set(root,1,tme,lid[i],{disc[col],0}); } void DelHLD(int col){ for(int i:nodes[col])Set(root,1,tme,lid[i],{N,1}); } pii GetHLD(int col){ pii ans={N,0}; for(int i:nodes[col]){ for(int j=i;dep[j]>=dep[lca[col]];j=par[head[j]][0]){ ans=ans+Get(root,1,tme,max(lid[head[j]],lid[lca[col]]),lid[j]); } } return ans; } void DFS(int u){ Rem(u); disc[u]=low[u]=++tid; stk.push(u);in[u]=1; AddHLD(u); int v; while(v=Get(u)){ DFS(v); low[u]=min(low[u],low[v]); } pii tmp=GetHLD(u); low[u]=min(low[u],tmp.first); has_out[u]=tmp.second>0; if(low[u]==disc[u]){ bool ok=1; int sz=0; do{ v=stk.top(); stk.pop(); in[v]=0; DelHLD(v); if(has_out[v])ok=0; sz++; }while(v!=u); if(ok)ans=min(ans,sz-1); } } int main(){ int n,k; scanf("%i %i",&n,&k); for(int i=1;i<=n;i++)up[i]=i; for(int i=1,u,v;i<n;i++)scanf("%i %i",&u,&v),E[u].pb(v),E[v].pb(u); Tree(1,0); HLD(1,0); st[0]={N,0}; for(int i=1;i<=n;i++)Set(root,1,n,i,{N,0}); for(int i=1;i<=n;i++)scanf("%i",&c[i]),nodes[c[i]].pb(i); for(int i=1;i<=k;i++){ lca[i]=nodes[i][0]; for(int j:nodes[i])lca[i]=LCA(lca[i],j); } ans=n; for(int i=1;i<=k;i++)if(!disc[i])DFS(i); printf("%i\n",ans); return 0; }

Compilation message (stderr)

capital_city.cpp: In function 'void Set(int&, int, int, int, std::pair<int, int>)':
capital_city.cpp:40:12: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   40 |  int mid=ss+se>>1;
      |          ~~^~~
capital_city.cpp: In function 'std::pair<int, int> Get(int, int, int, int, int)':
capital_city.cpp:48:12: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   48 |  int mid=ss+se>>1;
      |          ~~^~~
capital_city.cpp: In function 'int Get(int)':
capital_city.cpp:54:16: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   54 |  while(ptr[col]<nodes[col].size()&&dep[Find(nodes[col][ptr[col]])]<dep[lca[col]])ptr[col]++;
      |        ~~~~~~~~^~~~~~~~~~~~~~~~~~
capital_city.cpp:55:13: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   55 |  if(ptr[col]==nodes[col].size())return 0;
      |     ~~~~~~~~^~~~~~~~~~~~~~~~~~~
capital_city.cpp: In function 'void DFS(int)':
capital_city.cpp:83:9: warning: suggest parentheses around assignment used as truth value [-Wparentheses]
   83 |  while(v=Get(u)){
      |        ~^~~~~~~
capital_city.cpp: In function 'int main()':
capital_city.cpp:106:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  106 |  scanf("%i %i",&n,&k);
      |  ~~~~~^~~~~~~~~~~~~~~
capital_city.cpp:108:31: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  108 |  for(int i=1,u,v;i<n;i++)scanf("%i %i",&u,&v),E[u].pb(v),E[v].pb(u);
      |                          ~~~~~^~~~~~~~~~~~~~~
capital_city.cpp:113:28: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  113 |  for(int i=1;i<=n;i++)scanf("%i",&c[i]),nodes[c[i]].pb(i);
      |                       ~~~~~^~~~~~~~~~~~
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