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48-Rotate-Image.java
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48-Rotate-Image.java
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// Do note that this is for a sqaure matrix (NxN)
// The process is to first transpose the matrix and then reverse it
// Taking the first example: [[1,2,3],[4,5,6],[7,8,9]]
// After Transpose: [[1,4,7],[2,5,8],[3,6,9]]
// After Reversal: [[7,4,1],[8,5,2],[9,6,3]]
class Solution {
public void rotate(int[][] matrix) {
int N = matrix.length;
transpose(matrix, N);
reverse(matrix, N);
}
void transpose(int[][] matrix, int n) {
for (int i = 0; i < n; i++) {
for (int j = i + 1; j < n; j++) {
int temp = matrix[j][i];
matrix[j][i] = matrix[i][j];
matrix[i][j] = temp;
}
}
}
void reverse(int[][] matrix, int n) {
for (int i = 0; i < n; i++) {
for (int j = 0; j < n / 2; j++) {
int temp = matrix[i][j];
matrix[i][j] = matrix[i][n - 1 - j];
matrix[i][n - 1 - j] = temp;
}
}
}
}