Submission #299744

#	Time	Username	Problem	Language	Result	Execution time	Memory
299744		errorgorn	Ancient Books (IOI17_books)	C++14	50 / 100	194 ms	20088 KiB

books

#include "books.h"

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

#define ll long long
#define ii pair<int,int>
#define fi first
#define se second

#define rep(x,s,e) for (auto x=(s)-((s)>(e));x!=(e)-((s)>(e));((s)<(e)?x++:x--))
#define all(x) (x).begin(),(x).end()
#define sz(x) (int) (x).size()

int n;
vector<int> arr;

int fwd[1000005];
int bwd[1000005];

long long minimum_walk(std::vector<int> p, int s) {
	n=sz(p);
	arr=p;
	
	rep(x,0,n){
		if (x<arr[x]) fwd[x]++,fwd[arr[x]]--;
		else bwd[arr[x]]++,bwd[x]--;
	}
	
	rep(x,0,n) fwd[x+1]+=fwd[x],bwd[x+1]+=bwd[x];
	
	int l=0,r=n-1;
	while (l<s && max(fwd[l],bwd[l])==0) l++;
	while (s<=r && max(fwd[r],bwd[r])==0) r--;
	
	ll ans=0;
	rep(x,l,r+1){
		ans+=max({fwd[x],bwd[x],1});
	}
	
	return ans*2;
}

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