[Leetcode]Word Search

[timu]

Given a 2D board and a word, find if the word exists in the grid.

The word can be constructed from letters of sequentially adjacent cell, where "adjacent" cells are those horizontally or vertically neighboring. The same letter cell may not be used more than once.

For example,

Given board =

[
["ABCE"],
["SFCS"],
["ADEE"]
]

word = 

"ABCCED"

,
-> returns 

true

,
word = 

"SEE"

,
-> returns 

true

,
word = 

"ABCB"

,
-> returns 

false

.
[daima]

public boolean exist(char[][] board, String word) {
for(int i = 0; i < board.length; i++)
for(int j = 0; j < board[0].length; j++){
if(exist(board, i, j, word, 0))
return true;
}
return false;
}
private boolean exist(char[][] board, int i, int j, String word, int ind){
if(ind == word.length()) return true;
if(i > board.length-1 || i <0 || j<0 || j >board[0].length-1 || board[i][j]!=word.charAt(ind))
return false;
board[i][j]='*';
boolean result = exist(board, i-1, j, word, ind+1) ||
exist(board, i, j-1, word, ind+1) ||
exist(board, i, j+1, word, ind+1) ||
exist(board, i+1, j, word, ind+1);
board[i][j] = word.charAt(ind);
return result;
}