Submission #73491

#	Time	Username	Problem	Language	Result	Execution time	Memory
73491		mr_banana	Ancient Books (IOI17_books)	C++17	12 / 100	4 ms	636 KiB

books

#include <bits/stdc++.h>
#include "books.h"

using namespace std;
const int MN=1e5+100;
int mark[MN];
vector<pair<int,pair<int,int> >  > e;
int par[MN];
int root(int x){
    return par[x]==x?x:par[x]=root(par[x]);
}
bool merg(int u,int v){
    u=root(u),v=root(v);
    if(u==v){
        return 0;
    }
    par[v]=u;
    return 1;
}
long long minimum_walk(std::vector<int> p, int s) {
    int n=p.size();
    long long ans=0;
    int cnt=0;
    for(int i=0;i<n;i++){
        ans+=abs(p[i]-i);
        if(!mark[i] && p[i]!=i){
            int x=i;
            do{
                mark[x]=cnt;
                x=p[x];
            }while(x!=i);
            cnt++;
        }
    }
    for(int i=0;i<n;i++){
        if(p[i]!=i){
            for(int j=i+1;j<n;j++){
                if(p[j]!=j){
                    e.push_back({j-i,{mark[i],mark[j]}});
                    break;
                }
            }
        }
    }
    sort(e.begin(),e.end());
    for(int i=0;i<e.size();i++){
        if(merg(e[i].second.first,e[i].second.second)){
            ans+=2*e[i].first;
        }
    }
    if(ans){
        for(int i=0;i<n;i++){
            if(p[i]==i){
                ans+=2;
            }
            else{
                break;
            }
        }
    }
	return ans;
}

Compilation message (stderr)

books.cpp: In function 'long long int minimum_walk(std::vector<int>, int)':
books.cpp:46:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=0;i<e.size();i++){
                 ~^~~~~~~~~

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