java - Iterative Depth First Search To Find A String (2D Array) -

i'm trying create iterative approach boggle game. class contains fields 2d array of strings called "board" , has 2d array of booleans called "havevisit". method calls test 2 loops through whole board, finding positions of first character of target string, passes coordinates test2 method, returning list holding coordinates.

the return1index method takes 2d array coordinate @ creates int representative of coordinates corresponding 1d array it. return2dindex opposite , returns int array holding 2 coordinates.

public list<integer> test2(int row1, int row2, string findme){      string temp = findme;      list<integer> output = new arraylist<integer>();      if (board[row1][row2].charat(0) != findme.charat(0))         return output;      havevisit = new boolean[size][size];      int row = row1;       int column = row2;                                          output.add(return1dindex(row, column));                 havevisit[row][column] = true;                          //for each letter in string      for(int j = 0; j < temp.length(); j++)          //for every column , row combination         (int x = row - 1; x < row + 2 ; x++)            (int y = column - 1; y < column + 2 ; y++)                //if index valid , not visited               if (x > -1 && y > -1 && y < size && x < size && !havevisit[x][y])                  //if output same size string, return                  if(output.size() == findme.length())                     return output;                   //if character in board matches char we're looking                  if(board[x][y].charat(0) == temp.charat(j))                  {                     havevisit[x][y] = true;                     output.add(return1dindex(x, y));                      //update row , column indices                     row = x;                     column = y;                  }               }            }      return output;   } 

for reason method works 50% of time. method works fine finding letters when they're arranged left right or top bottom, finding words right left or bottom top never works except 1 case: when you're searching string of length 1 or 2, method works.

i have working recursive solution wanted try way. thoughts why wouldn't work?

edit: code works right left, still not work when attempting search upwards.

i don't know problem is, there few suspects:

• you updating row , column indices while checking neighbors. removing element array while iterating through it: it's defined, has tricky semantics. suggest either bailing out (greedy algorithm) or keeping stack of matches (deeper search, requires saving stack of visited cells too).

• the fors missing opening braces, closing braces there, suggesting missing code.

• i'm not familiar boggle, isn't possible letter have 2 similar neighbors, axa? doing output.add(return1dindex(x, y)); may outputting 2 ways same letter. may end output longer findme.

my suggestion follow more standard format of depth-first search while iron out bugs. wikipedia has non-recursive pseudocode implementation, example: https://en.wikipedia.org/wiki/depth-first_search#pseudocode .