Submission #289178

#	Time	Username	Problem	Language	Result	Execution time	Memory
289178		wdjpng	Ancient Books (IOI17_books)	C++17	0 / 100	122 ms	376 KiB

books

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

#define rep(i,n) for(int i = 0; i < n; i++)
#define lint long long
using namespace std;

vector<int>fen;
int n;

void up(int i, int val){
	i++;
	for(; i <=n; i+=i&-i){
		fen[i]+=val;
	}
}

int get(int i){
	i++;
	int s=0;
	for(;i>0;i-=i&-i){
		s+=fen[i];
	}
	return s;
}

int get_range(int l, int r){
	return get(r) - get(l-1);
}

lint getCost(int end, int s, vector<int>const&p){

	fen.resize(n+1);
	vector<bool>unhappy(n);
	rep(i,n)
		if(p[i]!=i&&i!=end) {up(i,1); unhappy[i]=true;}
	
	lint cost=0;
	
	while(get(n-1)>0){
		int begin=-1, e=n;
		while(e-begin>1){
			int cur = (begin+e)/2;
			if(get_range(max(0, s-cur), min(n-1, s+cur)))
			{
				e=cur;
			} else 
			{
				begin=cur;
			}
		}

		
		if(unhappy[max(0, s-e)])
		{
			s=max(0, s-e);
		} else if (unhappy[min(n-1, s+e)])
		{
			s=min(n-1, s+e);
		}

		cost+=e;
		up(s, -1);
		unhappy[s]=false;
		cost+=abs(p[s]-s);
		s=p[s];
	}

	if(p[end]!=end){cost+=abs(s-end)+abs(end-p[end]);}
	return cost;
}

long long minimum_walk(std::vector<int> p, int s) {
	n = p.size();
	
	lint minn=1e19;
	rep(i, n){
		minn=min(minn, getCost(i,s,p));
	}

	return minn;
}

Compilation message (stderr)

books.cpp: In function 'long long int minimum_walk(std::vector<int>, int)':
books.cpp:76:12: warning: overflow in conversion from 'double' to 'long long int' changes value from '1.0e+19' to '9223372036854775807' [-Woverflow]
   76 |  lint minn=1e19;
      |            ^~~~

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