CODEWITHSUNDEEP
javaarraysmultidimensional-array
chris007
chris007

Reputation: 3

start searching in a 2 dimensional array from a sertent element java

I am trying to write a code that searches through a 2 dimensional array and tries to find the closest element to "x" that is empty, if "x" has any data in. The elements' coordinates are given from another method. For example "x" is (3,2). If there's no empty element then the code must continue searching in the whole array.

public void find(int row, int column) {
    for (int i = row - 1; i < row + 2; i++) {
        for (int k = column - 1; k < column + 2; k++) {

            if (this.arr[i][k].equals(" ")) {
                System.out.println(i + "," + k + " is empty.");
                return;
            }
        }

    }
}

I am looking foreword for any helpful suggestions on how to code this method. Thank you.

Upvotes: 0

Views: 116

Answers (1)

Marin Relatic
Marin Relatic

Reputation: 238

Under assumptions

  • this is matrix (each row has equal num of columns)
  • method arguments are valid: 0 <= row < numOfRows and 0 <= column < numOfColumns

this code will do search of 2 dimensional array around specified element in the way you've described. Note that this is not clock direction round search around specified element, but search from top left corner to bottom right corner (from top to bottom and from left to right)

public void find(int row, int column) {
        int distance = 1;
        int numOfRows = arr.length;
        int numOfColumns = 0;
        if (arr.length > 0) {
            numOfColumns = arr[0].length;
        }
        int maxDistance = Math.max(numOfRows, numOfColumns);        
        for (distance = 1; distance < maxDistance; distance ++) {
            for (int i = Math.max(row - distance, 0); i <= Math.min(row + distance, numOfRows - 1); i++) {
                if (Math.abs(i - row) == distance) {
                    // Check row
                    for (int k = Math.max(column - distance, 0); k <= Math.min(column + distance, numOfColumns - 1); k++) {
                        if (arr[i][k] == null || arr[i][k].trim().isEmpty()) {
                            System.out.println((i+1) + "," + (k+1) + " is empty.");
                            return;
                        } else {
                            System.out.println((i+1) + "," + (k+1) + " is not empty.");
                        }
                    }
                } else {
                    // Check only edge elements
                    int k = column - distance;
                    if (k >= 0) {
                        if (arr[i][k] == null || arr[i][k].trim().isEmpty()) {
                            System.out.println((i+1) + "," + (k+1) + " is empty.");
                            return;
                        } else {
                            System.out.println((i+1) + "," + (k+1) + " is not empty.");
                        }
                    }
                    k = column + distance;
                    if (k < numOfColumns) {
                        if (arr[i][k] == null || arr[i][k].trim().isEmpty()) {
                            System.out.println((i+1) + "," + (k+1) + " is empty.");
                            return;
                        } else {
                            System.out.println((i+1) + "," + (k+1) + " is not empty.");
                        }
                    }
                }
            }
        }
        System.out.println("No empty elements");
    }

Upvotes: 1

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