solved word-search.

Author: sangbeenmoon

word-search/sangbeenmoon.py

@@ -0,0 +1,36 @@
+# TC : O(m * n * 4^L)
+# SC : O(m * n + L)
+
+class Solution:
+    answer = False
+    dx = [0,0,-1,1]
+    dy = [-1,1,0,0]
+
+    def exist(self, board: List[List[str]], word: str) -> bool:
+        
+        for yy in range(len(board)):
+            for xx in range(len(board[0])):
+                if board[yy][xx] == word[0]:
+                    self.visited = [ [False] * len(board[0]) for _ in range(len(board))]
+                    self.visited[yy][xx] = True
+                    self.dfs(board, word, xx, yy, 0)
+                    
+
+        return self.answer
+
+    def dfs(self, board, word, cx, cy, idx):
+        print(cx, cy, idx)
+        if idx == len(word) - 1:
+            self.answer = True
+
+        for i in range(4):
+            nx = cx + self.dx[i]
+            ny = cy + self.dy[i]
+
+            if 0 <= nx and nx < len(board[0]):
+                if 0 <= ny and ny < len(board):
+                    if self.visited[ny][nx] == False:
+                        if idx + 1 <= len(word) - 1 and word[idx+1] == board[ny][nx]:
+                            self.visited[ny][nx] = True
+                            self.dfs(board, word, nx, ny, idx + 1)
+                            self.visited[ny][nx] = False