word search solution

Author: devyejin

word-search/devyejin.py

@@ -0,0 +1,30 @@
+class Solution:
+    def exist(self, board: list[list[str]], word: str) -> bool:
+        def backtrack(x, y, idx):
+            if idx == len(word):
+                return True
+
+            if not (0 <= x < m and 0 <= y < n) or board[x][y] != word[idx]:
+                return False
+
+            tmp, board[x][y] = board[x][y], "@"
+
+            res = (
+                    backtrack(x + 1, y, idx + 1) or
+                    backtrack(x - 1, y, idx + 1) or
+                    backtrack(x, y + 1, idx + 1) or
+                    backtrack(x, y - 1, idx + 1)
+            )
+
+            board[x][y] = tmp
+            return res
+
+        m = len(board)
+        n = len(board[0])
+
+        for r in range(m):
+            for c in range(n):
+                if backtrack(r, c, 0):
+                    return True
+
+        return False