Submission #410846

#	Time	Username	Problem	Language	Result	Execution time	Memory
410846		DavidDamian	Cave (IOI13_cave)	C++11	100 / 100	395 ms	508 KiB

cave

#include <iostream>
#include "cave.h"
using namespace std;
int status[5005];
int door[5005];
int locked[5005];

///Binary Search
///Update ranges
///Greedy
void reset(int n, int L, int R, int correct) ///Set segment of array to correct
{
    for (int i = L; i <= R; i++) {
        if (locked[i]) continue;
        status[i] = correct;
    }
}

int binarySearch(int n, int i, int correct) ///Perform binary search on i-th door
{
    int L = 0, R = n - 1;
    while (L < R) {
        int mid = (L + R) / 2;
        reset(n, L, mid, correct);
        reset(n, mid + 1, R, !correct);
        if (tryCombination(status) != i)
            R = mid;
        else
            L = mid + 1;
    }
    return L;
}

void exploreCave(int N) {
    for (int i = 0; i < N; i++) {
        reset(N, 0, N, 0);
        int ans = tryCombination(status); //Obtain correct state for door
        int correct = (ans == i);
        int sw = binarySearch(N, i, correct);
        status[sw] = correct;
        door[sw] = i;
        locked[sw] = 1; //Mantain that door open in order to see beyond
    }
    answer(status, door);
}

• Subtask 1: 12 / 12
• Subtask 2: 13 / 13
• Subtask 3: 21 / 21
• Subtask 4: 30 / 30
• Subtask 5: 24 / 24