adding word search

Author: daiyongg-kim

word-search/daiyongg-kim.py

@@ -0,0 +1,28 @@
+class Solution:
+        
+    def exist(self, board: List[List[str]], word: str) -> bool:
+        row = len(board)
+        col = len(board[0])
+
+        def dfs(i: int, j: int, k: int):
+            if k == len(word):
+                return True
+            
+            if i < 0 or i >= row or j < 0 or j >= col or board[i][j] != word[k]:
+                return False
+
+            current = board[i][j]
+            board[i][j] = ''
+
+            if dfs(i-1, j, k+1) or dfs(i+1, j, k+1) or dfs(i, j-1, k+1) or dfs(i, j+1, k+1):
+                return True
+            
+            board[i][j] = current
+            return False
+
+        for i in range(row):
+            for j in range(col):
+                if dfs(i, j, 0):
+                    return True
+        
+        return False