Update 212 solution

halfrost · dezhiy · commit 325e5130b714 · 2021-10-08T19:50:33.000-07:00
diff --git a/website/content/ChapterFour/0200~0299/0212.Word-Search-II.md b/website/content/ChapterFour/0200~0299/0212.Word-Search-II.md
@@ -54,6 +54,52 @@ func findWords(board [][]byte, words []string) []string {
 	return res
 }
 
+// these is 79 solution
+var dir = [][]int{
+	{-1, 0},
+	{0, 1},
+	{1, 0},
+	{0, -1},
+}
+
+func exist(board [][]byte, word string) bool {
+	visited := make([][]bool, len(board))
+	for i := 0; i < len(visited); i++ {
+		visited[i] = make([]bool, len(board[0]))
+	}
+	for i, v := range board {
+		for j := range v {
+			if searchWord(board, visited, word, 0, i, j) {
+				return true
+			}
+		}
+	}
+	return false
+}
+
+func isInBoard(board [][]byte, x, y int) bool {
+	return x >= 0 && x < len(board) && y >= 0 && y < len(board[0])
+}
+
+func searchWord(board [][]byte, visited [][]bool, word string, index, x, y int) bool {
+	if index == len(word)-1 {
+		return board[x][y] == word[index]
+	}
+	if board[x][y] == word[index] {
+		visited[x][y] = true
+		for i := 0; i < 4; i++ {
+			nx := x + dir[i][0]
+			ny := y + dir[i][1]
+			if isInBoard(board, nx, ny) && !visited[nx][ny] && searchWord(board, visited, word, index+1, nx, ny) {
+				return true
+			}
+		}
+		visited[x][y] = false
+	}
+	return false
+}
+
+
 ```
 
 
