Submission #1034959

#	Time	Username	Problem	Language	Result	Execution time	Memory
1034959		vjudge1	Ancient Books (IOI17_books)	C++17	50 / 100	1501 ms	144248 KiB

books

#include "books.h"
#include<bits/stdc++.h>
using namespace std;
int par[1001000],sz[1001000];
int abp(int n){
    return par[n]?par[n]=abp(par[n]):n;
}
int merge(int a,int b){
    a=abp(a+1);b=abp(b+1);
    if(a-b)par[a]=b,
        sz[b]+=sz[a];
    return a!=b;
}
set<int>notanedge,ST;
map<int,int>mp;
int s_;
void mergefrom(int l,int r){
    ST.insert(l),ST.insert(r);
    while(notanedge.lower_bound(l)!=notanedge.lower_bound(r)){
        int k=*notanedge.lower_bound(l);
        merge(k,k+1);
        notanedge.erase(k);
        mp[k];mp[k+1];
    }
}
long long minimum_walk(std::vector<int> p, int s) {
    s_=s;
    long long ans=0;
    int n=p.size(),K=0;
    for(int i=0;i<n-1;i++)
        notanedge.insert(i);
    for(int i=0;i<n;i++) if(i-p[i])
        ans+=abs(i-p[i]), mergefrom(i,p[i]);
    if(ST.empty())return 0;
    vector<tuple<int,int,int>>v;
    for(auto [i,j]:mp){
        auto it=mp.upper_bound(i);
        if(it!=mp.end())
            v.push_back({it->first-i,i,it->first});
    }
    sort(v.begin(),v.end());
    for(auto [w,x,y]:v)
        ans+=w*2*merge(x,y);
    int ans2=min(abs(*ST.begin()-s),abs(*--ST.end()-s));
    return ans+2*ans2;
}

Compilation message (stderr)

books.cpp: In function 'long long int minimum_walk(std::vector<int>, int)':
books.cpp:29:20: warning: unused variable 'K' [-Wunused-variable]
   29 |     int n=p.size(),K=0;
      |                    ^

• Subtask 1: 12 / 12
• Subtask 2: 10 / 10
• Subtask 3: 28 / 28
• Subtask 4: 0 / 20
• Subtask 5: 0 / 30