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Learning Opportunities

This puzzle can be solved using the following concepts. Practice using these concepts and improve your skills.



Langton's ant is a turing machine built on simple rules:
• Consider a grid of WxH squares, each of which can be either black # or white ..
• The ant starts at the position (x, y) of the grid, the upper left square coordinates are (0,0).
• The ant is facing one of the following directions (N = up, E = right, S = down, W = left).
• The ant moves T turns. For each turn:
  - it rotates 90° left if it is on a white square, 90° right otherwise.
  - it inverts the color of the square it is located on.
  - it moves 1 square forward in its current direction.

From an arbitrarily coloured grid and the ant's initial state, you have to print the grid state after T turns.

On the given test cases, the ant never has to go out of bounds.
Ligne 1 : Two integers W and H for the width and height of the grid.
Ligne 2 : Two integers x and y for the ant's initial coordinates.
Ligne 3 : A character N, E, S or W for the ant's initial direction.
Ligne 4 : An integer T for the number of turns.
H following lines : A line of size W composed of # (black square) and . (white square) for the initial state of the grid.
H lines representing the final state of the grid.
1 ≤ W, H ≤ 30
0 ≤ x < W
0 ≤ y < H
0 ≤ T ≤ 1000
5 5
2 2

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