Find a specific word(diagonally) in 2D matrix

Question

"Given a 2D char array and a string.

find if the specific string appears diagonally in the matrix".

private static boolean diagonalContains(char[][] grid,String word){
    int wordLength = word.length();
    char[] wordArray = word.toCharArray();
    for(int i =0, length = grid.length; i < length; i++){
        loop:for(int j =0, k = i, subLength = grid[i].length;
                j < subLength && k >= wordLength; j++, k--){
            for(int l =0; l < wordLength; l++){
                if(grid[j + l][k - l]!= wordArray[l]){
                    continue loop;
                }
                return true;
            }
        }
    }
}

The function asks me to return value, although I did, thus I am not able to run the code. I've tried to put return statement in different regions of the code but none seems to be working. Plus I would like to know if the code is efficient for the purpose of the exercise?

Answer 1

Basically, there are two problems
1. Every function should return some value, if the return type is not void. In your case, a return value is specified only if the criteria is satisfied. You are supposed to return false, otherwise.

  private static boolean diagonalContains(char[][] grid,String word){
    int wordLength = word.length();
    char[] wordArray = word.toCharArray();
    for(int i =0, length = grid.length; i < length; i++){
      loop:for(int j =0, k = i, subLength = grid[i].length;
      j < subLength && k >= wordLength; j++, k--){
        for(int l =0; l < wordLength; l++){
          if(grid[j + l][k - l]!= wordArray[l]){
            continue loop;
          }
          return true;
        }
      }
    }
    return false;
  }

2. The code seems to be inefficient and the logic seems to be wrong. So try the following code.

import java.util.*;
    class WordDiagonal{
      public static void main(String[] args){

        char grid[][] = {{'a','b','c'},{'d','e','f'},{'g','h','i'}};

        if(checkDiagonalSubstring(grid,"aei")){
          System.out.println("Contains..");
        }else{
          System.out.println("Sorry..!");

        }

      }


      private static boolean checkDiagonalSubstring(char[][] grid, String word){

        String diagonalString = "";
        Integer i = 0;

        for(char[] charArray : grid){
          diagonalString += charArray[i++];
        }

        if(diagonalString.contains(word)){
          return true;
        }

        return false;
      }

    }