LeetCode – Rotate Image (Java)
You are given an n x n 2D matrix representing an image.
Rotate the image by 90 degrees (clockwise).
Follow up:
Could you do this in-place?
In-place Solution
By using the relation "matrix[i][j] = matrix[n-1-j][i]", we can loop through the matrix.
public void rotate(int[][] matrix) { int n = matrix.length; for (int i = 0; i < n / 2; i++) { for (int j = 0; j < Math.ceil(((double) n) / 2.); j++) { int temp = matrix[i][j]; matrix[i][j] = matrix[n-1-j][i]; matrix[n-1-j][i] = matrix[n-1-i][n-1-j]; matrix[n-1-i][n-1-j] = matrix[j][n-1-i]; matrix[j][n-1-i] = temp; } } } |
<pre><code> String foo = "bar"; </code></pre>
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