#3 Daily Problems -RotateImage

Arun Pandian M
1 min readJul 21, 2020

Hi friends, This is my third day coding practice in problem solving

Problem :

Note: Try to solve this task in-place (with O(1) additional memory), since this is what you'll be asked to do during an interview.

You are given an n x n 2D matrix that represents an image. Rotate the image by 90 degrees (clockwise).

Example

For

a = [[1, 2, 3],
[4, 5, 6],
[7, 8, 9]]

the output should be

rotateImage(a) =
[[7, 4, 1],
[8, 5, 2],
[9, 6, 3]]

Input/Output

  • [execution time limit] 3 seconds (java)
  • [input] array.array.integer a
  • Guaranteed constraints:
    1 ≤ a.length ≤ 100,
    a[i].length = a.length,
    1 ≤ a[i][j] ≤ 104.
  • [output] array.array.integer

My solution:

int[][] rotateImage(int[][] a) {int colLenght = a[0].length;int rowLength = a.length;int[][] r = new int[rowLength][colLenght];for(int i = 0; i < a.length; i++) {for(int j = a.length - 1, rc = 0; j >= 0 && rc < a.length; j--, rc++) {r[i][rc] = a[j][i];}}return r;}

Hello again The above things are my solution to this array rotation to 90 degree in colck wise. Please give me some advice to improve this solution. Lets meet tomorrow guys

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Arun Pandian M

Senior Android developer at FundsIndia, A time investor to learn new things about Programming. Currently in a relationship with Green Bug(Android).