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Programming challenge: rotating a matrix 90 degrees in place
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// Programming challenge: rotating a matrix 90 degrees in place | |
// Original post: https://blog.svpino.com/2015/05/10/programming-challenge-rotating-a-matrix-90-degrees-in-place | |
public class RotatingMatrix90DegreesInPlace { | |
private static int[][] matrix = { | |
{ 1, 2, 3, 4 }, | |
{ 5, 6, 7, 8 }, | |
{ 9, 10, 11, 12 }, | |
{ 13, 14, 15, 16 } | |
}; | |
private final static int N = 4; | |
private static void print() { | |
for (int i = 0; i < N; i++) { | |
for (int j = 0; j < N; j++) { | |
System.out.print("\t" + matrix[i][j]); | |
} | |
System.out.println(); | |
} | |
System.out.println(); | |
} | |
public static void main(String[] args) { | |
print(); | |
for (int ring = 0; ring < N / 2; ring++) { | |
int farthest = N - ring - 1; | |
for (int i = ring; i < farthest; i++) { | |
int temp = matrix[ring][i]; | |
matrix[ring][i] = matrix[farthest - i + ring][ring]; | |
matrix[farthest - i + ring][ring] = | |
matrix[farthest][farthest - i + ring]; | |
matrix[farthest][farthest - i + ring] = | |
matrix[i][farthest]; | |
matrix[i][farthest] = temp; | |
} | |
} | |
print(); | |
} | |
} |
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I did it in two steps,
First build the Transpose
Then Swap columns
I feel this solution is easier to implement , I dont know. :)
https://gist.github.com/Qassas/1336b9c6d27fcd933d4bea8f76e40827#file-programming-challenge-rotating-a-matrix-90-degrees-in-place-cpp