Create 079. Word Search.java

Author: futurus

079. Word Search.java

@@ -0,0 +1,56 @@
+// https://leetcode.com/problems/word-search
+
+public class Solution {
+    public boolean helper(char[][]board, String word, boolean[][] visited, int r, int c) {
+        if (word.length() == 0) { 
+            return true; 
+        }
+        else {
+            char nChar = word.charAt(0);
+            visited[r][c] = true;
+            if (r - 1 >= 0 
+                && !visited[r-1][c] 
+                && board[r-1][c] == nChar 
+                && helper(board, word.substring(1, word.length()), visited, r-1, c)) {
+                    return true;
+            }
+            if (r + 1 < board.length 
+                && !visited[r+1][c] 
+                && board[r+1][c] == nChar
+                && helper(board, word.substring(1, word.length()), visited, r+1, c)) {
+                    return true;
+            }
+            if (c - 1 >= 0 
+                && !visited[r][c-1] 
+                && board[r][c-1] == nChar
+                && helper(board, word.substring(1, word.length()), visited, r, c-1)) {
+                    return true;
+            }
+            if (c + 1 < board[r].length 
+                && !visited[r][c+1] 
+                && board[r][c+1] == nChar
+                && helper(board, word.substring(1, word.length()), visited, r, c+1)) {
+                    return true;
+            }
+            visited[r][c] = false;
+            
+            return false;
+        }
+    }
+    
+    public boolean exist(char[][] board, String word) {
+        boolean[][] visited = new boolean[board.length][board[0].length];
+        if (board.length * board[0].length >= word.length()) {
+            for (int r = 0; r < board.length; r++) {
+                for (int c = 0; c < board[r].length; c++) {
+                    if (board[r][c] == word.charAt(0)) {
+                        if(helper(board, word.substring(1, word.length()), visited, r, c)) 
+                            return true;
+                    }
+                }
+            }
+        }
+        
+        return false;
+    }
+}