Submission #1114473

#	Time	Username	Problem	Language	Result	Execution time	Memory
1114473		vjudge1	Osmosmjerka (COCI17_osmosmjerka)	C++14	160 / 160	865 ms	72496 KiB

osmosmjerka

#include <bits/stdc++.h>
using namespace std;
#define _for(i, a, b) for (int i = (a); i < (int)(b); ++i)
typedef unsigned int uint;
typedef long long LL;
typedef unsigned long long ULL;
const int D[][2] = {{1, 0},  {0, 1},  {0, -1}, {-1, 0},
                    {1, -1}, {-1, 1}, {1, 1},  {-1, -1}},
          NN = 500 + 4, LK = 21;
const uint Base[2] = {1183531, 1041221};
inline LL gcd(LL a, LL b) { return b == 0 ? a : gcd(b, a % b); }
int N, M;
LL K;
char S[NN][NN];
uint BP[2][LK + 4];  // BP[i,l]: Base[i]^(2^l)
struct HashVal {
  uint h[2];
  HashVal() { h[0] = h[1] = 0; }
  inline void append(const HashVal &x, int len) {
    _for(i, 0, 2) h[i] = (h[i] * BP[i][len]) + x.h[i];
  }
  ULL val() { return ((ULL)h[0] << 32) + h[1]; }
};
HashVal H[NN][NN][LK + 4];
unordered_map<ULL, int> HC;
int mod(int x, int md) { return ((x % md) % md + md) % md; }
int main() {
  scanf("%d %d %lld\n", &N, &M, &K);
  for (int i = 0; i < N; i++) scanf("%s", S[i]);
  BP[0][0] = Base[0], BP[1][0] = Base[1];
  for (int l = 1; l <= LK; l++)
    _for(i, 0, 2) BP[i][l] = (BP[i][l - 1] * BP[i][l - 1]);
  _for(i, 0, N) _for(j, 0, M) H[i][j][0].h[0] = H[i][j][0].h[1] = S[i][j] - 'a';
  _for(di, 0, 8) {
    int dx = D[di][0], dy = D[di][1];
    LL len = 1;
    for (int l = 1; l <= LK; l++) {
      _for(x, 0, N) _for(y, 0, M) {
        (H[x][y][l] = H[x][y][l - 1])
            .append(H[mod(x + dx * len, N)][mod(y + dy * len, M)][l - 1],
                    l - 1);
      }
      len *= 2;
    }
    _for(x, 0, N) _for(y, 0, M) {
      len = K;
      HashVal h;
      for (int l = LK, nx = x, ny = y; l >= 0; l--)
        if ((1 << l) & len) {
          len -= (1 << l), h.append(H[nx][ny][l], l);
          nx = mod(nx + dx * (1 << l), N), ny = mod(ny + dy * (1 << l), M);
        }
      HC[h.val()]++;
    }
  }
  LL x = 0, y = 1LL * (N * M * 8) * (N * M * 8);
  for (auto p : HC) x += 1LL * (p.second) * (p.second);
  LL g = gcd(x, y);
  printf("%lld/%lld\n", x / g, y / g);
  return 0;
}

Compilation message (stderr)

osmosmjerka.cpp: In function 'int main()':
osmosmjerka.cpp:28:8: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   28 |   scanf("%d %d %lld\n", &N, &M, &K);
      |   ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~
osmosmjerka.cpp:29:36: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   29 |   for (int i = 0; i < N; i++) scanf("%s", S[i]);
      |                               ~~~~~^~~~~~~~~~~~

• Subtask 1: 160 / 160