Submission #663344

#	Time	Username	Problem	Language	Result	Execution time	Memory
663344		Alma	Cave (IOI13_cave)	C++17	100 / 100	832 ms	692 KiB

cave

#include <bits/stdc++.h>
#include "cave.h"
using namespace std;

const int MX = 5000;
int S[MX], D[MX], A[MX], idx[MX];

void exploreCave(int N) {
    memset(S, 0, sizeof S);
    memset(D, -1, sizeof D);

    for (int n = 0; n < N; n++) {

        for (int i = 0; i < N; i++) {
            if (D[i] != -1) {
                A[i] = idx[D[i]];
            } else {
                A[i] = 1;
            }
        }

        int ret = tryCombination(A);
        int target;
        if (ret == n) {
            target = 0;
        } else {
            target = 1;
        } 

        int lo = 0, mid, res = -1, hi = N-1;
        while (lo <= hi) {

            mid = (lo+hi) / 2;
            for (int i = 0; i < N; i++) {
                if (D[i] != -1) continue;
                if (i <= mid) {
                    A[i] = target;
                } else {
                    A[i] = 1 - target;
                }
            }

            ret = tryCombination(A);
            if (ret == n) {
                lo = mid+1;
            } else {
                res = mid;
                hi = mid-1;
            }
        }

        idx[n] = target;
        S[res] = target;
        D[res] = n;
    }

    answer(S, D);
}

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