Submission #108656

#	Time	Username	Problem	Language	Result	Execution time	Memory
108656		someone_aa	Library (JOI18_library)	C++17	0 / 100	557 ms	868 KiB

library

#include <cstdio>
#include <vector>
#include "library.h"
#include <bits/stdc++.h>
#define ll long long
#define pb push_back
using namespace std;
const int maxn = 1500;
vector<int>adj[maxn];
vector<int>M;
int n;


int preQuery(vector<int>M) {
    int br = 0;
    for(int i:M) {
        if(i == 1) br++;
    }

    if(br == 0) return 0;
    else return Query(M);
}

int find_neighbour(int x, int l=1, int r=n) {
    if(l > r) return -1;

    if(l == r) {
        // check if X is connected to L or not

        M[l-1] = M[x-1] = 1;
        int curr = preQuery(M);
        M[l-1] = M[x-1] = 0;

        if(curr == 1) return l;
        else return -1;
    }

    int mid = (l + r) /2;
    for(int i=l-1;i<=mid-1;i++) {
        M[i] = 1;
    }

    for(int i:adj[x]) {
        M[i-1] = 0;
    }

    M[x-1] = 0;

    int Without = preQuery(M);
    M[x-1] = 1;
    int With = preQuery(M);
    M[x-1] = 0;

    for(int i=l-1;i<=mid-1;i++) {
        M[i] = 0;
    }

    if(With <= Without) {
        return find_neighbour(x, l, mid);
    }
    else {
        return find_neighbour(x, mid+1, r);
    }
}

void Solve(int N) {
    n = N;
	for(int i=0;i<N;i++) {
		M.pb(0);
	}

	if(N == 1) {
        vector<int>v;
        v.pb(1);
        Answer(v);
        return;
	}

	int st = 1;
    bool check = false;
    int br = 0;
    for(int i=0;i<N;i++) {
        int X;
        if(st == 1) {
            if(br == 0) {
                X = find_neighbour(st);
                br++;
            }
            else if(br == 1) {
                X = find_neighbour(st);
                br++;
            }
            else {
                break;
            }
        }
        else {
            X = find_neighbour(st);
        }

        if(X == -1) {
            // st is on corner
            if(st == 1) {
                break;
            }
            else {
                st = 1;
            }
        }
        else {
            adj[st].pb(X);
            adj[X].pb(st);
            st = X;
        }
    }

    if(adj[1].size() == 1) return;

    /*for(int i=1;i<=n;i++) {
        cout<<i<<": \n";
        for(int j:adj[i]) {
            cout<<j<<" ";
        } cout<<"\n";
    }*/


    st = 1;
    bool found = false;
    for(int i=1;i<=N;i++) {
        if(adj[i].size() == 1) {
            st = i;
            found = true;
            break;
        }
    }

    if(!found) {
        return;
    }

    vector<int>v;
    v.pb(st);
    st = adj[st][0];
    for(int i=0;i<N-1;i++) {
        if(adj[st][0] == v.back()) {
            v.pb(st);
            st = adj[st][1];
        }
        else {
            v.pb(st);
            st = adj[st][0];
        }
    }
    Answer(v);
}

Compilation message (stderr)

library.cpp: In function 'void Solve(int)':
library.cpp:80:10: warning: unused variable 'check' [-Wunused-variable]
     bool check = false;
          ^~~~~

• Subtask 1: 0 / 19
• Subtask 2: 0 / 81