Submission #854506

#	Time	Username	Problem	Language	Result	Execution time	Memory
854506		vjudge1	Sjekira (COCI20_sjekira)	C++17	0 / 110	84 ms	54360 KiB

sjekira

#ifndef Local
    #pragma GCC optimize("O3,unroll-loops")
    #pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
#endif
#include <bits/stdc++.h>
#define int long long
#define pb push_back
#define lim 100005
using namespace std;
const int mod=1000000007ll;

int parent[lim];
int maxi[lim];
int find(int i){
    if(parent[i]==i){
        return i;
    }
    return parent[i]=find(parent[i]);
}
int fm(int i){
    return maxi[find(i)];
}
void unite(int i,int j){
    int x=find(i),y=find(j);
    if(x!=y){
        maxi[y]=maxi[x]=max(maxi[x],maxi[y]);
        parent[y]=x;
    }
}

unordered_set<int>v[lim];
void solve(){
    int n;
    cin>>n;
    int h[n];
    for(int i=0;i<n;i++){
        cin>>h[i];
    }
    for(int i=0;i<n-1;i++){
        int x,y;
        cin>>x>>y;
        x--,y--;
        v[x].insert(y);
        v[y].insert(x);
    }
    for(int i=0;i<n;i++){
        parent[i]=i;
        maxi[i]=h[i];
    }
    set<array<int,3>>all;
    for(int i=0;i<n;i++){
        for(int j:v[i]){
            all.insert({fm(i)+fm(j),min(i,j),max(i,j)});
        }
    }
    int ans=0;
    while(all.size()){
        //cerr<<all.size()<<"\n";
        auto p=*all.begin();
        all.erase(p);
        //cerr<<all.size()<<"\n";
        v[p[0]].erase(p[1]);
        v[p[1]].erase(p[0]);
        if(fm(p[1])>fm(p[2])){
            swap(p[2],p[1]);
        }
        ans+=p[0];
        for(int i:v[p[1]]){
            if(!all.empty()&&all.count({fm(p[1])+fm(i),min(p[1],i),max(p[1],i)})){
                //cerr<<all.size()<<"hmm1\n";
                all.erase({fm(p[1])+fm(i),min(p[1],i),max(p[1],i)});
                //cerr<<all.size()<<"hmm2\n";
                all.insert({fm(p[2])+fm(i),min(p[1],i),max(p[1],i)});
            }
        }
        /*
        for(auto p:all){
            cerr<<p[0]<<" "<<p[1]<<" "<<p[2]<<"\n";
        }
        */
        unite(p[1],p[2]);
    }
    cout<<ans<<"\n";
}

signed main(){
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);cout.tie(NULL);
#ifdef Local  
    freopen("in","r",stdin);
    freopen("out","w",stdout);
#endif
    int t=1;
    //cin>>t;
    while (t--)
    {
        solve();
    }
}

• Subtask 1: 0 / 10
• Subtask 2: 0 / 10
• Subtask 3: 0 / 30
• Subtask 4: 0 / 60