Submission #402763

#	Time	Username	Problem	Language	Result	Execution time	Memory
402763		blue	Unscrambling a Messy Bug (IOI16_messy)	C++17	100 / 100	3 ms	492 KiB

messy

#include "messy.h"
#include <string>
#include <vector>
using namespace std;

int N;
vector<int> p;

void find_p(int a, int b, vector<int> goodcells)
//goodcells contains all the elements i with a <= p_inv[i] <= b
{
    if(a == b)
    {
        p[goodcells[0]] = a;
        return;
    }

    string base_query(N, '1');
    for(int g: goodcells)
        base_query[g] = '0';


    vector<int> goodcells_1, goodcells_2;

    for(int g: goodcells)
    {
        string query = base_query;
        query[g] = '1';

        if(check_element(query))
            goodcells_1.push_back(g);
        else
            goodcells_2.push_back(g);
    }

    find_p(a, (a+b)/2, goodcells_1);
    find_p((a+b)/2+1, b, goodcells_2);
}

vector<int> restore_permutation(int n, int w, int r)
{
    N = n;
    for(int g = n; g >= 2; g /= 2) //size of gap
    {
        for(int i = 0; i < n; i += g) //starting point of gap
        {
            for(int o = 0; o < g/2; o++)
            {
                string s(n, '1');
                for(int j = i; j < i+g; j++)
                    if(j-i != o)
                        s[j] = '0';
                add_element(s);
            }
        }
    }

    compile_set();

    // cerr << n << '\n';
    vector<int> goodcells;
    for(int i = 0; i < n; i++) goodcells.push_back(i);

    p = vector<int>(n);
    find_p(0, n-1, goodcells);

    return p;
}

• Subtask 1: 20 / 20
• Subtask 2: 18 / 18
• Subtask 3: 11 / 11
• Subtask 4: 21 / 21
• Subtask 5: 30 / 30