Find pattern in matrix - Java Data Structure

Java examples for Data Structure:Matrix

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Description

Find pattern in matrix

Demo Code

public class Main{
  public static void main(String[] args) {
    int[][] matrix = new int[][] { 
      { 7, 2, 8, 3, 4, 5, 5, 8, 6, 4 }, 
      { 6, 7, 3, 1, 1, 5, 8, 6, 1, 9 },/* w  w w .j a  va 2 s. c o m*/
      { 8, 9, 8, 8, 2, 4, 2, 6, 4, 3 }, 
      { 3, 8, 3, 9, 5, 0, 5, 3, 2, 4 }, 
      { 9, 5, 0, 9, 5, 1, 5, 8, 1, 3 },
      { 3, 8, 4, 3, 8, 4, 5, 3, 8, 4 }, 
      { 6, 4, 7, 3, 5, 3, 0, 2, 9, 3 }, 
      { 7, 0, 5, 3, 1, 0, 6, 6, 0, 1 },
      { 0, 8, 3, 4, 2, 8, 2, 9, 5, 6 }, 
      { 4, 6, 0, 7, 9, 2, 4, 1, 3, 7 }, 
      { 4, 6, 0, 7, 9, 2, 4, 1, 3, 7 } };
    int[][] pattern = new int[][] { 
      { 9, 5, 0 }, 
      { 3, 8, 4 }, 
      { 3, 5, 3 } };

    System.out.println(findPattern(matrix, pattern).toString());

  }

  public static class Result {
    int R;
    int C;

    public Result(int R, int C) {
      this.R = R;
      this.C = C;
    }

    @Override
    public String toString() {
      return R + "--" + C;
    }
  }
  public static Result findPattern(int[][] matrix, int[][] pattern) {
    if (matrix.length < pattern.length || matrix[0].length < pattern[0].length) {
      return new Result(-1, -1);
    }

    int count = 0;
    for (int i = 0; i < matrix[0].length - pattern[0].length + 1; i++) {
      for (int j = 0; j < matrix.length - pattern.length + 1; j++) {
        count++;
        int I = i;
        int J = j;
        if (match(matrix, I, J, pattern)) {
          return new Result(I, J);
        }
      }
    }
    return new Result(-1, -1);
  }
  public static boolean match(int[][] matrix, int i, int j, int[][] pattern) {
    int J = j;
    for (int m = 0; m < pattern[0].length; m++) {
      for (int n = 0; n < pattern.length; n++) {
        if (matrix[i][j] != pattern[m][n]) {
          System.out.println(" NO " + pattern[m][n] + " --- " + matrix[i][j] + " ");
          return false;
        } else {

          System.out.println(j + " --- " + i + " ");
          j++;
        }
      }
      i++;
      j = J;
    }
    System.out.println("");
    return true;
  }
}

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