ctci/1. Arrays and strings/1.7. matrix_rotation.java

34 lines
1.0 KiB
Java

public static boolean rotate(int[][] matrix) {
int n = matrix.length;
if (n == 0 || n != matrix[0].length) return false; // Not a square
for (int layer = 0; layer < n/2; layer++) {
int first = layer;
int last = n - 1 - layer;
for(int i = first; i < last; i++) {
int offset = i - first;
int top = matrix[first][i]; // save top
// left -> top
matrix[first][i] = matrix[last-offset][first];
// bottom -> left
matrix[last-offset][first] = matrix[last][last - offset];
// right -> bottom
matrix[last][last - offset] = matrix[i][last];
// top -> right
matrix[i][last] = top; // right <- saved top
}
}
return true;
}
public static void main(String[] args) {
int[][] matrix = AssortedMethods.randomMatrix(3, 3, 0, 9);
AssortedMethods.printMatrix(matrix);
rotate(matrix);
System.out.println();
AssortedMethods.printMatrix(matrix);
}