Create Amazon-RoverControl.md

Author: koji

Amazon-RoverControl.md

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+## Amazon | OA | Rover Control
+
+Amazon Online Assessment: https://leetcode.com/discuss/interview-question/985703/Amazon-or-OA-or-Rover-Control
+
+ A Mars rover is directed to move within a square matrix. It accepts a sequence of 
+ commands to move in any of the four directions from each cell: [UP, DOWN, LEFT or 
+ RIGHT]. The rover starts from cell 0. and may not move diagonally or outside of 
+ the boundary.
+
+ Each cell in the matrix has a position equal to:
+ (row * size) + column
+ where row and column are zero-indexed, size = row length of the matrix.
+
+ Return the final position of the rover after all moves.
+
+ Example
+ n = 4
+ commands = [RIGHT, UP, DOWN, LEFT, DOWN, DOWN]
+
+ The rover path is shown below.
+
+ 0 1 2 3
+ 4 5 6 7
+ 8 9 10 11
+ 12 13 14 15
+
+ RIGHT: Rover moves to position 1
+ UP: Position unchanged, as the move would take the rover out of the boundary.
+ DOWN: Rover moves to Position 5.
+ LEFT: Rover moves to position 4
+ DOWN: Rover moves to position 8
+ DOWN: The rover ends up in position 12.
+
+ The function returns 12.
+
+ Function Description
+ Complete the function roverMove in the editor below.
+ roverMove has the following parameter(s):
+ int n: the size of the square matrix
+ string cmds[m]: the commands
+
+ Returns
+ int: the label of the cell the rover occupies after executing all commands
+
+ Constraints
+ 2 <= n <= 20
+ 1 <= |cmds| <= 20
+
+ Input Format For Custom Testing
+
+ Input from stdin will be processed as follows and passed to the function.
+ The first line contains an integer, n, denoting the size of the square matrix.
+ The next line contains an integer, m, the number of commands to follow.
+ Each of the next m lines contains a command string, cmds[i].
+
+ Sample Input :
+ STDIN Function
+
+ 4 → n = 4
+ 5 → cmds [] size m = 5
+ RIGHT → cmds = ['RIGHT', 'DOWN', 'LEFT', 'LEFT', 'DOWN']
+ DOWN
+ LEFT
+ LEFT
+ DOWN
+
+ Sample Output:
+ 8
+
+ Explanation:
+ 0 1 2 3
+ 4 5 6 7
+ 8 9 10 11
+ 12 13 14 15
+ Rover starts at position 0
+ RIGHT → pos 1
+ DN → pos 5
+ LEFT → pos 4
+ LEFT → pos 4, No effect
+ DOWN → pos 8
+ '''
+
+
+```python
+def rover(n, cmds):
+ pos = 0
+ for c in cmds:
+ if c == 'UP':
+ if pos//n >=1:
+ pos -= n 
+ elif c == 'DOWN':
+ if pos//n < n-1:
+ pos += n
+ elif c == 'RIGHT':
+ if (pos % n) < n-1:
+ pos +=1
+ elif c == 'LEFT':
+ if (pos % n) >=1:
+ pos -= 1
+ return pos
+
+n = 4
+cmds = ['RIGHT', 'DOWN', 'LEFT', 'LEFT', 'DOWN'] # 8
+cmds2 = ['RIGHT', 'UP', 'DOWN', 'LEFT', 'DOWN', 'DOWN'] # 12
+expected_output2 = 8
+expected_output2 = 12
+output = rover(n, cmds)
+output2 = rover(n, cmds2)
+print(output)
+print(output == expected_output)
+print(output2)
+print(output2 == expected_output2)
+```