Problem p00606 (C++) — buggy submission, verdict: Time Limit Exceeded

#include <algorithm>
#include <cmath>
#include <stack>
#include <stdio.h>

using namespace std;

int b_row, b_col, memo[16][3][3];

char b[2];

bool rangeCheck(int row, int col) {
  if (row >= 0 && row <= 2 && col >= 0 && col <= 2)
    return true;
  else {
    return false;
  }
}

int translate(char ch) {
  switch (ch) {
  case 'A':
    return 0;
  case 'B':
    return 1;
  case 'C':
    return 2;
  case 'D':
    return 10;
  case 'E':
    return 11;
  case 'F':
    return 12;
  case 'G':
    return 20;
  case 'H':
    return 21;
  case 'I':
    return 22;
  }

  return -1; // must not reach here.
}

int main() {

  int n, tmp, energy_row, energy_col, row, col, div_row[4] = {-1, 0, 0, 1},
                                                div_col[4] = {0, -1, 1, 0};
  char start[2], energy[2];

  while (true) {
    scanf("%d", &n);
    if (n == 0)
      break;

    for (int i = 0; i < 16; i++) {
      for (int p = 0; p < 3; p++) {
        for (int k = 0; k < 3; k++)
          memo[i][p][k] = 0;
      }
    }

    scanf("%s %s %s", start, energy, b);

    tmp = translate(b[0]);
    b_row = tmp / 10;
    b_col = tmp % 10;

    tmp = translate(energy[0]);
    energy_row = tmp / 10;
    energy_col = tmp % 10;

    tmp = translate(start[0]);

    row = tmp / 10, col = tmp % 10;

    memo[0][row][col] = 1;

    for (int loop = 0; loop <= n - 1; loop++) {
      for (int i = 0; i < 3; i++) {
        for (int k = 0; k < 3; k++) {
          if (i != b_row || k != b_col) { //????????§????????´???
            for (int p = 0; p < 4; p++) {
              if (rangeCheck(i + div_row[p], k + div_col[p]) == true &&
                  (i + div_row[p] != b_row ||
                   k + div_col[p] !=
                       b_col)) { //?§????????????§??????????????????????????§??????
                memo[loop + 1][i + div_row[p]][k + div_col[p]] +=
                    memo[loop][i][k];
              } else { //?°?????????¨???1????????????????????????????????´?????????????????´??????????????¨????????´????????°???????????????
                memo[loop + 1][i][k] += memo[loop][i][k];
              }
            }
          }
        }
      }
    }

    printf("%.8lf\\n",
           ((double)memo[n][energy_row][energy_col]) / ((double)pow(4, n)));
  }

  return 0;
}

Error: TLE

Fixed submission:

#include <algorithm>
#include <cmath>
#include <stack>
#include <stdio.h>

using namespace std;

int map[3][3], b_row, b_col;

char b[2];

bool rangeCheck(int row, int col) {
  if (row >= 0 && row <= 2 && col >= 0 && col <= 2)
    return true;
  else {
    return false;
  }
}

int translate(char ch) {
  switch (ch) {
  case 'A':
    return 0;
  case 'B':
    return 1;
  case 'C':
    return 2;
  case 'D':
    return 10;
  case 'E':
    return 11;
  case 'F':
    return 12;
  case 'G':
    return 20;
  case 'H':
    return 21;
  case 'I':
    return 22;
  }

  return -1; // must not reach here.
}

void func(int rest, int row, int col) {
  if (rest == 0) {
    map[row][col]++;
    return;
  }

  if (rangeCheck(row, col - 1) == true && (row != b_row || col - 1 != b_col)) {
    func(rest - 1, row, col - 1);
  } else {
    func(rest - 1, row, col);
  }

  if (rangeCheck(row, col + 1) == true && (row != b_row || col + 1 != b_col)) {
    func(rest - 1, row, col + 1);
  } else {
    func(rest - 1, row, col);
  }

  if (rangeCheck(row - 1, col) == true && (row - 1 != b_row || col != b_col)) {
    func(rest - 1, row - 1, col);
  } else {
    func(rest - 1, row, col);
  }

  if (rangeCheck(row + 1, col) == true && (row + 1 != b_row || col != b_col)) {
    func(rest - 1, row + 1, col);
  } else {
    func(rest - 1, row, col);
  }
}

int main() {

  int n, tmp, energy_row, energy_col;
  char start[2], energy[2];

  while (true) {
    scanf("%d", &n);
    if (n == 0)
      break;

    for (int i = 0; i < 3; i++) {
      for (int k = 0; k < 3; k++)
        map[i][k] = 0;
    }

    scanf("%s %s %s", start, energy, b);

    tmp = translate(b[0]);
    b_row = tmp / 10;
    b_col = tmp % 10;

    tmp = translate(energy[0]);
    energy_row = tmp / 10;
    energy_col = tmp % 10;

    tmp = translate(start[0]);
    func(n, tmp / 10, tmp % 10);

    printf("%.8lf\\n",
           ((double)map[energy_row][energy_col]) / ((double)pow(4, n)));
  }

  return 0;
}