Word Search solution

Author: kimjunyoung90

word-search/kimjunyoung90.java

@@ -0,0 +1,42 @@
+class Solution {
+    public boolean exist(char[][] board, String word) {
+
+        int rows = board.length;
+        int columns = board[0].length;
+        boolean[][] visited = new boolean[rows][columns];
+        for (int i = 0; i < rows; i++) {
+            for (int j = 0; j < columns; j++) {
+                if (dfs(board, word, i, j, 0, visited)) {
+                    return true;
+                }
+            }
+        }
+        return false;
+    }
+
+    private boolean dfs(char[][] board, String word, int row, int col, int idx, boolean[][] visited) {
+        //예외 처리 1
+        if (idx == word.length()) return true;
+
+        //예외 처리 2
+        if (row < 0 || col < 0 || row >= board.length || col >= board[0].length) return false;
+
+        //예외 처리 3
+        if (visited[row][col]) return false;
+
+        //1. 글자 체크
+        if (board[row][col] != word.charAt(idx)) return false;
+
+        //방문 처리
+        visited[row][col] = true;
+
+        //상, 하, 좌, 우 찾기
+        boolean found = dfs(board, word, row + 1, col, idx + 1, visited)
+                || dfs(board, word, row - 1, col, idx + 1, visited)
+                || dfs(board, word, row, col + 1, idx + 1, visited)
+                || dfs(board, word, row, col - 1, idx + 1, visited);
+
+        visited[row][col] = false;
+        return found;
+    }
+}