Submission #58677

#	Time	Username	Problem	Language	Result	Execution time	Memory
58677		FLDutchman	Cave (IOI13_cave)	C++14	100 / 100	1576 ms	540 KiB

cave

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

typedef int INT;

#define pb push_back
#define FOR(i, l, r) for(int i = (l); i < (r); i++)
#define fst first
#define snd second
#define int long long

typedef vector<int> vi;
typedef pair<int, int> ii;
typedef vector<ii> vii;
typedef long long ll;

const int NMAX = 5000;
const ll INF = 1e15;
int N;
INT D[NMAX], S[NMAX];

int flip(int l, int r){
    int j = 0, ret = 0;
    FOR(i, 0, N) {
        if(D[i] == -1) {
            if(j == l) ret = i;
            if(j >= l and j < r) S[i] = !S[i];
            j++;
        }
    }
    return ret;
}

int query(){
    return tryCombination(S);
}

void exploreCave(INT n) {
    /* ... */
    N = n;
    FOR(i, 0, N) D[i] = -1, S[i] = 0;
    FOR(d, 0, N){
        // try for door d;
        // The unknown levers all start randomly, the others are in the correct position
        if(query() == d) flip(0, N-d);
        // pos is the index in D of the leftmost element of [l, r)
        int l = 0, r = N-d;
        while(l+1 != r){
            int m = (l+r)/2;
            flip(l, m);
            if( query() == d ) r = m, flip(l, r);
            else  l = m;
        }
        //cout << l << endl;
        int j = 0;
        FOR(i, 0, N) if(D[i] == -1) {
            if(j == l){  D[i] = d;}
            j++;
        }
    }
    answer(S, D);
}

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