Submission #722616

#	Time	Username	Problem	Language	Result	Execution time	Memory
722616		Ahmed57	Transport (COCI19_transport)	C++14	0 / 130	437 ms	14304 KiB

Main

#include <bits/stdc++.h>

using namespace std;
int sz[100007];long long all = 0;
int vis[100007];
vector<pair<long long,long long>> adj[100007];
bool ss = 0;
long long cost[100007];
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
#define ordered_set tree<pair<long long,long long>, null_type,less<pair<long long,long long>>, rb_tree_tag,tree_order_statistics_node_update>
ordered_set s;
vector<pair<int,int>> ch;
void calc(int no,int pr,long long dep,long long mi){
    if(!ss){//ending
        pair<long long,long long> p = {-dep,0};
        long long it = s.order_of_key(p);
        all+=s.size()-it;
    }else{//starting (reverse)
        if(dep>=mi){
            s.insert({dep,no});
            mi = dep;
        }
    }
    for(auto i:adj[no]){
        if(i.first==pr||vis[i.first])continue;
        calc(i.first,no,dep+((ss==1?cost[i.first]:cost[no])-i.second),mi);
    }
}
int dfs(int no,int pr){
    sz[no] = 1;
    for(auto i:adj[no]){
        if(i.first==pr||vis[i.first]!=0)continue;
        sz[no]+=dfs(i.first,no);
    }
    return sz[no];
}
int get_centroid(int no,int ss,int pr){
    for(auto i:adj[no]){
        if(pr==i.first||vis[i.first]!=0)continue;
        if(sz[i.first]*2>ss){
            return get_centroid(i.first,ss,no);
        }
    }
    return no;
}
void centroid(int no){
    int cen = get_centroid(no,dfs(no,-1),-1);
    vis[cen] = 1;
    //cout<<cen<<"\n";
    s.clear();ch.clear();
    s.insert({0,cen});
    for(auto i:adj[cen]){
        if(vis[i.first])continue;
        ss = 0;
        calc(i.first,-1,((ss==1?cost[i.first]:cost[cen])-i.second),0);
        ss = 1;
        calc(i.first,-1,((ss==1?cost[i.first]:cost[cen])-i.second),0);
        ch.push_back({i.first,i.second});
    }
    //cout<<all<<"h"<<endl;
    s.clear();
    while(!ch.empty()){
        ss = 0;
        calc(ch.back().first,-1,((ss==1?cost[ch.back().first]:cost[cen])-ch.back().second),0);
        ss = 1;
        calc(ch.back().first,-1,((ss==1?cost[ch.back().first]:cost[cen])-ch.back().second),0);
        ch.pop_back();
    }
    pair<long long,long long> p = {0,0};
    long long it = s.order_of_key(p);
    all+=s.size()-it;
    //cout<<all<<endl;
    for(auto i:adj[cen]){
        if(vis[i.first])continue;
        centroid(i.first);
    }
}
int main(){
    ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
    int n;
    cin>>n;
    for(int i = 1;i<=n;i++){
        cin>>cost[i];
    }
    for(int i = 0;i<n-1;i++){
        long long a,b,c;
        cin>>a>>b>>c;
        adj[a].push_back({b,c});
        adj[b].push_back({a,c});
    }
    centroid(1);
    cout<<all;
}

• Subtask 1: 0 / 13
• Subtask 2: 0 / 13
• Subtask 3: 0 / 13
• Subtask 4: 0 / 13
• Subtask 5: 0 / 13
• Subtask 6: 0 / 13
• Subtask 7: 0 / 13
• Subtask 8: 0 / 13
• Subtask 9: 0 / 13
• Subtask 10: 0 / 13