Submission #409131

#	Time	Username	Problem	Language	Result	Execution time	Memory
409131		victoriad	Fountain (eJOI20_fountain)	C++14	100 / 100	420 ms	31736 KiB

fountain

#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
#include <utility>
#include <queue>
#include <map>
#include <iomanip>
#include <stack>
#include <fstream>
using namespace std;
 vector<int>v;
 vector<int>d;
vector<vector<int> >up;
int search(int l,vector<int>&ps,int r){
    int low=0,hi=18,mid,re=-1;
    while(low<=hi){
        mid=low+(hi-low)/2;
        if(ps[up[r][mid]]>l){
            low=mid+1;
            re=mid;
        }
        else{
            hi=mid-1;
        }
    }
    if(re==-1)return 0;
    if(ps[up[r][1]]<=l)return up[r][re]+1;
    return search(l,ps,up[r][re]);
}
 void suma(vector<int>&ps,vector<vector<int> >&c,int nodo){
     if(up[nodo][1]==-1)ps[nodo]=v[nodo];
     else ps[nodo]=ps[up[nodo][1]]+v[nodo];
     for(int y:c[nodo]){
             suma(ps,c,y);
     }
 }
 
int main(){
  ios::sync_with_stdio(false);
   cin.tie(NULL);
    int n,q;
    cin>>n>>q;
    int l,r;
    v.resize(n);
    d.resize(n);
    for(int i=0;i<n;i++){
      cin>>d[i]>>v[i];
    }
    vector<vector<int> >con(n);
    up.resize(n);
    vector<int>a(28,-1);
    for(int i=0;i<n;i++)up[i]=a;
    for(int i=0;i<n;i++)up[i][0]=i;
    int an=-1,u=0;
    up[n-1][1]=-1;
    int x=d[n-1];
    priority_queue<pair<int,int> >pq;
    pq.push(make_pair(1e9-d[0],0));
    for(int i=1;i<n-1;i++){
        while(!pq.empty()){
            int p=pq.top().first;
            int k=pq.top().second;
            if(p>1e9-d[i]){
                up[k][1]=i;
                con[i].push_back(k);
                pq.pop();
            }
            else{
                break;
            }
        }
        pq.push(make_pair(1e9-d[i],i));
 
    }
    vector<int>ps(n,0);
    for (int i=0;i<n;i++){
        if(up[i][1]==-1){
            suma(ps,con,i);
        }
    }
 
    for(int l=2;l<18;l++){
        for(int i=0;i<n;i++){
            if(up[i][l-1]!=-1)up[i][l]=up[up[i][l-1]][l-1];
        }
    }
 
    for(int i=0;i<q;i++){
        cin>>r>>l;
        r--;
        if(l<=v[r])cout<<r+1<<"\n";
        else if(ps[r]-l<0)cout<<0<<"\n";
        else cout<<search(ps[r]-l,ps,r)<<"\n";
    }
    
    
  return 0;
}

Compilation message (stderr)

fountain.cpp: In function 'int main()':
fountain.cpp:56:9: warning: unused variable 'an' [-Wunused-variable]
   56 |     int an=-1,u=0;
      |         ^~
fountain.cpp:56:15: warning: unused variable 'u' [-Wunused-variable]
   56 |     int an=-1,u=0;
      |               ^
fountain.cpp:58:9: warning: unused variable 'x' [-Wunused-variable]
   58 |     int x=d[n-1];
      |         ^

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