rotate matrix - Java Data Structure

Java examples for Data Structure:Matrix

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Description

rotate matrix

Demo Code


public class Main {

  public void rotate(int[][] matrix) {
    if (matrix == null)
      return;//w  w w .jav a2  s . c  om
    int N = matrix.length;
    for (int i = 0; i < N / 2; i++) // This is the layer
      for (int j = i; j < N - i - 1; j++) { // This is the offset to start
        // swap
        int t = matrix[i][j];
        matrix[i][j] = matrix[N - j - 1][i];
        matrix[N - j - 1][i] = matrix[N - i - 1][N - j - 1];
        matrix[N - i - 1][N - j - 1] = matrix[j][N - i - 1];
        matrix[j][N - i - 1] = t;
      }
  }

  public static void main(String[] args) {
    int[][] matrix = { { 1, 2, 3, 4, 5 }, { 6, 7, 8, 9, 10 }, { 11, 12, 13, 14, 15 }, { 16, 17, 18, 19, 20 },
        { 21, 22, 23, 24, 25 } };
    for (int i = 0; i < matrix.length; i++) {
      for (int j = 0; j < matrix[0].length; j++)
        System.out.print(matrix[i][j] + " ");
      System.out.print("\n");
    }
    new Main().rotate(matrix);
    System.out.print("\n");
    System.out.print("\n");
    System.out.print("\n");

    for (int i = 0; i < matrix.length; i++) {
      for (int j = 0; j < matrix[0].length; j++)
        System.out.print(matrix[i][j] + " ");
      System.out.print("\n");
    }
  }

}

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