Submission #1275185

#	Time	Username	Problem	Language	Result	Execution time	Memory
1275185		warrenn	Fountain (eJOI20_fountain)	C++20	100 / 100	427 ms	29928 KiB

fountain

#include<bits/stdc++.h>
using namespace std;
#define int long long 

const int maxn=1e5;
int n,qu,d[maxn+2],c[maxn+2],val[maxn+2],par[maxn+2];;
vector<int>adj[maxn+2];
int bin[maxn+2][20];

void dfs(int cur,int tot,int p){
    par[cur]=p;
    val[cur]=tot;
    for(auto x : adj[cur]){
        dfs(x,tot+c[x],cur);
    }
}

signed main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);cout.tie(0);
    cin>>n>>qu;   
    for(int q=1;q<=n;q++){
        cin>>d[q]>>c[q];
    }
    d[n+1]=1e18; c[n+1]=0;

    stack<int>st;
    st.push(n+1);
    for(int q=n;q>=1;q--){
        while(st.size() && d[st.top()]<=d[q]){
            st.pop();
        }
        adj[st.top()].push_back(q);
        st.push(q);
    } 

    dfs(n+1,0,0);
    for(int q=1;q<=n;q++){
        bin[q][0]=par[q];
    }
    for(int q=1;q<20;q++){
        for(int w=1;w<=n;w++){
            bin[w][q]=bin[bin[w][q-1]][q-1];
        }
    }

    while(qu--){
        int r,v;
        cin>>r>>v;
        if(val[r]<v){
            cout<<0<<endl;
            continue;
        }
        if(c[r]>=v){
            cout<<r<<endl;
            continue;
        }

        int cur=r;
        for(int q=19;q>=0;q--){
            if(val[r]-val[bin[bin[cur][q]][0]]<v){
                cur=bin[cur][q];
               
            }
        }
        
       
        cur=par[cur];
        if(cur==n+1)cur=0;
        cout<<cur<<endl;
    }
}

• Subtask 1: 30 / 30
• Subtask 2: 30 / 30
• Subtask 3: 40 / 40