Submission #482425

#	Time	Username	Problem	Language	Result	Execution time	Memory
482425		chenwz	Osmosmjerka (COCI17_osmosmjerka)	C++14	160 / 160	2039 ms	82848 KiB

osmosmjerka

#include <bits/stdc++.h>
#include <cstdio>
#include <map>
using namespace std;

#define _for(i, a, b) for (int i = (a); i < (int)(b); ++i)
typedef unsigned int uint;
typedef long long LL;
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 Item {
  uint h[2];
  void add(const Item &x, int len) {

    for (int i = 0; i < 2; i++) {
      h[i] = (h[i] * BP[i][len]) /*%Mod[i]*/ + x.h[i];
      //  h[i]%=Mod[i];
    }
  }
  bool operator<(const Item &x) const {
    _for(i, 0, 2) if (h[i] != x.h[i]) return h[i] < x.h[i];
    return false;
  }
};
Item f[NN][NN][LK + 4];
map<Item, int> cnt;

int main() {
  scanf("%d %d %lld\n", &N, &M, &K);
  for (int i = 0; i < N; i++)
    scanf("%s", S[i]);
  for (int di = 0; di < 8; di++) {
    BP[0][0] = Base[0], BP[1][0] = Base[1];
    for (int i = 1; i <= LK; i++) {
      BP[0][i] = (BP[0][i - 1] * BP[0][i - 1]) /*%Mod[0]*/;
      BP[1][i] = (BP[1][i - 1] * BP[1][i - 1]) /*%Mod[1]*/;
    }

    _for(i, 0, N) _for(j, 0, M) {
      f[i][j][0].h[0] = S[i][j] - 'a' /*%Mod[0]*/;
      f[i][j][0].h[1] = S[i][j] - 'a' /*%Mod[1]*/;
    }

    int dx = D[di][0], dy = D[di][1];
    LL len = 1;
    for (int l = 1; l <= LK; l++) {
      for (int i = 0; i < N; i++)
        for (int j = 0; j < M; j++) {
          f[i][j][l] = f[i][j][l - 1];
          f[i][j][l].add(f[((i + dx * len) % N + N) % N]
                          [((j + dy * len) % M + M) % M][l - 1],
                         l - 1);
        }
      len *= 2;
    }
    for (int i = 0; i < N; i++)
      for (int j = 0; j < M; j++) {
        len = K;
        Item t;
        int x = i, y = j;
        t.h[0] = t.h[1] = 0;
        for (int log = LK; log >= 0; log--)
          if ((1 << log) & len) {
            len -= (1 << log);
            t.add(f[x][y][log], log);
            x = ((x + dx * (1 << log)) % N + N) % N;
            y = ((y + dy * (1 << log)) % M + M) % M;
          }
        cnt[t]++;
      }
  }
  LL x = 0, y = 1LL * (N * M * 8) * (N * M * 8);
  for (const auto p : cnt)
    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:37:8: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   37 |   scanf("%d %d %lld\n", &N, &M, &K);
      |   ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~
osmosmjerka.cpp:39:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   39 |     scanf("%s", S[i]);
      |     ~~~~~^~~~~~~~~~~~

• Subtask 1: 160 / 160