UVa 10016 - Flip-Flop the Squarelotron

Accepted date: 2013-10-29
Ranking (as of 2013-10-29): 35 out of 701
Language: C++

/*
  UVa 10016 - Flip-Flop the Squarelotron

  To build using Visual Studio 2012:
    cl -EHsc -O2 UVa_10016_Flip_Flop_the_Squarelotron.cpp
*/

#include <algorithm>
#include <cstdio>
using namespace std;

const int n_max = 100;
int matrix[n_max][n_max];

/*
For the rgi-th ring (rgi >= 0), the corresponding elements of matrix are:
  matrix[rgi][rgi] - matrix[rgi][n - 1 - rgi] // top row
  matrix[n - 1 - rgi][rgi] - matrix[n - 1 - rgi][n - 1 - rgi] // bottom row

  matrix[rgi][rgi] - matrix[n - 1 - rgi][rgi] // left column
  matrix[rgi][n - 1 - rgi] - matrix[n - 1 - rgi][n - 1 - rgi] // right column
*/

enum {upside_down = 1, left_right, main_diagonal, main_inverse_diagonal};

void upside_down_flip(int n, int rgi)
{
  for (int c = rgi; c < n - rgi; c++)
    swap(matrix[rgi][c], matrix[n - 1 - rgi][c]);
  for (int r = rgi + 1; r < n / 2; r++) {
    swap(matrix[r][rgi], matrix[n - 1 - r][rgi]);
    swap(matrix[r][n - 1 - rgi], matrix[n - 1 - r][n - 1 - rgi]);
  }
}

void left_right_flip(int n, int rgi)
{
  for (int r = rgi; r < n - rgi; r++)
    swap(matrix[r][rgi], matrix[r][n - 1 - rgi]);
  for (int c = rgi + 1; c < n / 2; c++) {
    swap(matrix[rgi][c], matrix[rgi][n - 1 - c]);
    swap(matrix[n - 1 - rgi][c], matrix[n - 1 - rgi][n - 1 - c]);
  }
}

void main_diagonal_flip(int n, int rgi)
{
  for (int c = rgi + 1; c < n - rgi; c++)
    swap(matrix[rgi][c], matrix[c][rgi]);
  for (int c = rgi + 1; c < n - rgi - 1; c++)
    swap(matrix[n - 1 - rgi][c], matrix[c][n - 1 - rgi]);
}

void main_inverse_diagonal_flip(int n, int rgi)
{
  for (int c = rgi; c < n - rgi - 1; c++)
    swap(matrix[rgi][c], matrix[n - 1 - c][n - 1 - rgi]);
  for (int c = rgi + 1; c < n - rgi - 1; c++)
    swap(matrix[n - 1 - rgi][c], matrix[n - 1 - c][rgi]);
}

int main()
{
  int m;
  scanf("%d", &m);
  while (m--) {
    int n;
    scanf("%d", &n);
    for (int r = 0; r < n; r++)
      for (int c = 0; c < n; c++)
        scanf("%d", &matrix[r][c]);
    for (int rgi = 0, nr_rings = (n + 1) / 2; rgi < nr_rings; rgi++) {
      int t;
      scanf("%d", &t);
      while (t--) {
        int c;
        scanf("%d", &c);
        switch (c) {
        case upside_down:
          upside_down_flip(n, rgi);
          break;
        case left_right:
          left_right_flip(n, rgi);
          break;
        case main_diagonal:
          main_diagonal_flip(n, rgi);
          break;
        case main_inverse_diagonal:
          main_inverse_diagonal_flip(n, rgi);
          break;
        }
#ifdef DEBUG
        for (int r = 0; r < n; r++)
          for (int c = 0; c < n; c++)
            fprintf(stderr, "%d%c", matrix[r][c], ((c == n - 1) ? '\n' : ' '));
#endif
      }
    }
    for (int r = 0; r < n; r++)
      for (int c = 0; c < n; c++)
        printf("%d%c", matrix[r][c], ((c == n - 1) ? '\n' : ' '));
  }
  return 0;
}