Submission #268657

#	Time	Username	Problem	Language	Result	Execution time	Memory
268657		DavidDamian	Library (JOI18_library)	C++11	100 / 100	368 ms	512 KiB

library

#include<bits/stdc++.h>
#include "library.h"
using namespace std;
///Binary Search with gaps
set<int> S; //Set with non fixed numbers
vector<int> Q;
vector<int> Q2;
vector<int> disc;
bool inRange(int L,int R)
{
    for(int i=L;i<=R;i++){
        Q[i-1]=1; //Fills the whole range
        if(disc[i-1]==0) Q2[i-1]=1; //Fills the whole range if and only if the number is still in S (not discovered)
    }
    int A=Query(Q); //Query with the numbers in the range + previous discovered numbers
    int B=Query(Q2); //Query only with new numbers
    for(int i=L;i<=R;i++){ //Reset the arrays
        Q2[i-1]=0;
        if(!disc[i-1]) Q[i-1]=0;
    }
    return A==B; //If the answers are same, then there is one number adjacent to the last discovered, in Range is true
}
int binarySearch(int N)
{
    int L=1;
    int R=N;
    int x;
    while(L<R){
        int mid=(L+R)/2;
        auto it=S.lower_bound(L);
        int minimum=(*it);
        if(minimum<=mid && inRange(L,mid))
            R=mid;
        else
            L=mid+1;
    }
    if(L==R) x=L;
    return x;
}
void Solve(int N)
{
	vector<int> ANS(N);
	if(N==1){
        ANS[0]=1;
        Answer(ANS);
        return;
	}
	Q.resize(N);
	Q2.resize(N);
	disc.resize(N);
	for(int i=1;i<=N;i++){
        S.insert(i);
        Q[i-1]=1;
	}
	for(int i=1;i<=N;i++){
        Q[i-1]=0;
        if(Query(Q)==1){
            ANS[0]=i;
            S.erase(i);
            disc[i-1]=1;
            break;
        }
        Q[i-1]=1;
	}
	for(int i=1;i<=N;i++){
        Q[i-1]=0;
	}
	Q[ ANS[0]-1 ]=1;
	int i=1;
	while(S.size()){
        int nxt=binarySearch(N);
        ANS[i++]=nxt;
        S.erase(nxt);
        disc[nxt-1]=1;
        Q[nxt-1]=1;
	}
	Answer(ANS);
}

Compilation message (stderr)

library.cpp: In function 'int binarySearch(int)':
library.cpp:38:12: warning: 'x' may be used uninitialized in this function [-Wmaybe-uninitialized]
   38 |     return x;
      |            ^

• Subtask 1: 19 / 19
• Subtask 2: 81 / 81