Submission #533110

#	Time	Username	Problem	Language	Result	Execution time	Memory
533110		DanerZein	Road Closures (APIO21_roads)	C++14	0 / 100	2084 ms	23672 KiB

roads

#include "roads.h"
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<ll,ll> ii;
typedef vector<ii> vi;
typedef pair<ii,ll> iii;
const int MAX_N=2e5+10;
bool vis[MAX_N];
int pa[MAX_N];
vector<vi> G;
int n;
void init(int n){
  for(int i=0;i<n;i++)
    pa[i]=i;
}
int findset(int x){
  if(pa[x]==x) return x;
  return pa[x]=findset(pa[x]);
}
bool issameset(int i,int j){
  return findset(i)==findset(j);
}
void unionset(int i,int j){
  if(!issameset(i,j)){
    int u=findset(i),v=findset(j);
    pa[u]=v;
  }
}
ll dp[MAX_N];
int path[MAX_N];
int ti;
ll knap(int u,int p){
  if(dp[u]!=-1) return dp[u];
  ll ans=0;
  for(auto &v:G[u]){
    if(v.first!=p){
      ans+=knap(v.first,u);
      if(!issameset(v.first,u)) ans+=v.second;
    }
  }
  ll s=ans;
  int id=-1;
  for(auto &v:G[u]){
    if(v.first!=p && !issameset(v.first,u)){
      ll rp=s;
      rp=rp-dp[v.first]-v.second;
      for(auto &z:G[v.first]){
	if(z.first!=u && !issameset(z.first,v.first)){
	  rp+=dp[z.first];
	  if(!issameset(z.first,v.first))
	     rp+=z.second;
	}
      }
      if(ans>rp){
	ans=rp;
	id=v.first;
      }
    }
  }
  path[u]=id;
  return dp[u]=ans;
}
void dfs(int u,int p){
  for(auto &v:G[u]){
    if(v.first!=p && v.first!=path[u]) dfs(v.first,u);
  }
  if(path[u]!=-1){
    unionset(u,path[u]);
    for(auto &v:G[path[u]]){
      if(v.first!=u){
	dfs(v.first,path[u]);
      }
    }
  }
}
std::vector<long long> minimum_closure_costs(int N, std::vector<int> U,
                                             std::vector<int> V,
                                             std::vector<int> W) {
  n=N;
  vector<ll> res;
  vector<iii> ed;
  G.resize(n+1);
  ll s=0;
  for(int i=0;i<n-1;i++){
    int a=U[i],b=V[i],w=W[i];
    G[a].push_back(ii(b,w));
    G[b].push_back(ii(a,w));
    ed.push_back(iii(ii(a,b),w));
    s+=w;
  }
  res.push_back(s);
  init(n);
  for(int i=0;i<n-1;i++){
    ti=i;
    memset(dp,-1,sizeof dp);
    memset(path,-1,sizeof path);
    res.push_back(knap(0,0));
    dfs(0,0);
  }
  return res;
}

• Subtask 1: 0 / 5
• Subtask 2: 0 / 7
• Subtask 3: 0 / 14
• Subtask 4: 0 / 10
• Subtask 5: 0 / 17
• Subtask 6: 0 / 25
• Subtask 7: 0 / 22