Answer to Question #167129 in Python for prathyusha

Question

You are given a square matrix A of dimensions NxN. You need to apply the below given 3 operations on the matrix A.

Rotation: It is represented as R S where S is an integer in {90, 180, 270, 360, 450, ...} which denotes the number of degrees to rotate. You need to rotate the matrix A by angle S in the clockwise direction. The angle of rotation(S) will always be in multiples of 90 degrees.

Update: It is represented as U X Y Z. In initial matrix A (as given in input), you need to update the element at row index X and column index Y with value Z.

After the update, all the previous rotation operations have to be applied to the updated initial matrix.

Querying: It is represented as Q K L. You need to print the value at row index K and column index L of the matrix A. Input

The first line contains a single integer N.

Next N lines contain N space-separated integers Aij (i - index of the row, j - index of the column).

Next lines contain various operations on the array. Each operation on each line (Beginning either with R, U or Q).

-1 will represent the end of input.Output

For each Query operation print the element present at row index K and colum index L of the matrix in its current state.Explanation

For Input:

2

1 2

3 4

R 90

Q 0 0

Q 0 1

R 90

Q 0 0

U 0 0 6

Q 1 1

-1

Initial Matrix

1 2

3 4

For R 90, clockwise rotation by 90 degrees, the matrix will become

3 1

4 2

For Q 0 0, print the element at row index 0 and column index 0 of A, which is 3.

For Q 0 1, print the element at row index 0 and column index 1 of A, which is 1.

Again for R 90, clockwise rotation by 90 degrees, the matrix will become

4 3

2 1

For Q 0 0, print the element at row index 0 and column index 0 of A, which is 4.

For U 0 0 6, update the value at row index 0 and column index 1 in the initial matrix to 6. So the updated matrix will be,

6 2

3 4

After updating, we need to rotate the matrix by sum of all rotation angles applied till now(i.e. R 90 and R 90 => 90 + 90 => 180 degrees in clockwise direction).

After rotation the matrix will now become

4 3

2 6

Next for Q 1 1, print the element at row index 1 and column index 1 of A, which is 6.

output

3

1

4

6

11

46

Errors/Warnings:

Traceback (most recent call last):

 File "main.py", line 46, in <module>

  query(matrix, args)

 File "main.py", line 23, in query

  i, j = map(int, _args)

ValueError: too many values to unpack (expected 2)

output:

11

46

23

Answer 1

def rotateMatrix(mat):

  

    if not len(mat):

        return

      

    """

        top : starting row index

        bottom : ending row index

        left : starting column index

        right : ending column index

    """

  

    top = 0

    bottom = len(mat)-1

  

    left = 0

    right = len(mat[0])-1

  

    while left < right and top < bottom:

  

        # Store the first element of next row,

        # this element will replace first element of

        # current row

        prev = mat[top+1][left]

  

        # Move elements of top row one step right

        for i in range(left, right+1):

            curr = mat[top][i]

            mat[top][i] = prev

            prev = curr

  

        top += 1

  

        # Move elements of rightmost column one step downwards

        for i in range(top, bottom+1):

            curr = mat[i][right]

            mat[i][right] = prev

            prev = curr

  

        right -= 1

  

        # Move elements of bottom row one step left

        for i in range(right, left-1, -1):

            curr = mat[bottom][i]

            mat[bottom][i] = prev

            prev = curr

  

        bottom -= 1

  

        # Move elements of leftmost column one step upwards

        for i in range(bottom, top-1, -1):

            curr = mat[i][left]

            mat[i][left] = prev

            prev = curr

  

        left += 1

  

    return mat