Submission #1104191

#	Time	Username	Problem	Language	Result	Execution time	Memory
1104191		Ianis	Cave (IOI13_cave)	C++17	100 / 100	237 ms	840 KiB

cave

#pragma GCC optimize("Ofast,unroll-loops")
#include "cave.h"
#include <iostream>

using namespace std;

#ifdef LOCAL
#include <stdio.h>
#include <stdlib.h>
#include "cave.h"

#define MAX_N 5000
#define MAX_CALLS 70000

#define fail(s, x...) do { \
		fprintf(stderr, s "\n", ## x); \
		exit(1); \
	} while(0)

/* Symbol obfuscation */
#define N koala
#define realS kangaroo
#define realD possum
#define inv platypus
#define num_calls echidna

static int N;
static int realS[MAX_N];
static int realD[MAX_N];
static int inv[MAX_N];
static int num_calls;

void answer(int S[], int D[]) {
    int i;
    int correct = 1;
    for (i = 0; i < N; ++i)
        if (S[i] != realS[i] || D[i] != realD[i]) {
            correct = 0;
            break;
        }

    if (correct)
        printf("CORRECT\n");
    else
        printf("INCORRECT\n");

    for (i = 0; i < N; ++i) {
        if (i > 0)
            printf(" ");
        printf("%d", S[i]);
    }
    printf("\n");

    for (i = 0; i < N; ++i) {
        if (i > 0)
            printf(" ");
        printf("%d", D[i]);
    }
    printf("\n");

    exit(0);
}

int tryCombination(int S[]) {
    int i;

    if (num_calls >= MAX_CALLS) {
        printf("INCORRECT\nToo many calls to tryCombination().\n");
        exit(0);
    }
    ++num_calls;

    for (i = 0; i < N; ++i)
        if (S[inv[i]] != realS[inv[i]])
            return i;
    return -1;
}

int init() {
    int i, res;

    FILE *f = fopen("cave.in", "r");
	if (!f)
		fail("Failed to open input file.");

	res = fscanf(f, "%d", &N);

    for (i = 0; i < N; ++i) {
        res = fscanf(f, "%d", &realS[i]);
    }
    for (i = 0; i < N; ++i) {
        res = fscanf(f, "%d", &realD[i]);
        inv[realD[i]] = i;
    }

    num_calls = 0;
    return N;
}
#endif

const int NMAX = 5005;

int n;
int a[NMAX];
int ans[NMAX];
int pos[NMAX];
int swi[NMAX];

int query(int s[]) {
   int q = tryCombination(s);
   return q == -1 ? n : q;
}

void make_seq(bool val, short l, short r, int cnt) {
   fill(a, a + n, !val);
   fill(a + l, a + r + 1, val);
   for (int i = 0; i < cnt; i++) {
      a[swi[i]] = ans[swi[i]];
   }
}

int find_switch(int door) {
   int l = 0, r = n - 1;
   bool val = 1;

   make_seq(1, 0, n - 1, door);
   if (query(a) <= door) {
      val = 0;
   }

   while (l <= r) {
      int mid = (l + r) >> 1;
      make_seq(val, l, mid, door);
      if (query(a) <= door) {
         l = mid + 1;
      } else {
         r = mid - 1;
      }
   }

   swi[door] = r + 1;
   ans[r + 1] = val;

   return r + 1;
}

void exploreCave(int N) {
   n = N;

   for (int i = 0; i < n; i++) {
      int x = find_switch(i);
      pos[x] = i;
   }

   make_seq(0, n, n, n);

   answer(a, pos);
}

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