solve 5

Author: lylaminju

word-search-ii/pmjuu.py

@@ -0,0 +1,46 @@
+'''
+시간 복잡도: O(m * n * 4^s) s = word 최대 길이
+공간 복잡도: O(w)           w = 모든 단어에 포함된 문자 수의 합
+'''
+from typing import List
+
+class Solution:
+    def findWords(self, board: List[List[str]], words: List[str]) -> List[str]:
+        root = {}
+        for word in words:
+            node = root
+
+            for char in word:
+                if char not in node:
+                    node[char] = {}
+                node = node[char]
+            
+            node['$'] = word
+
+        def dfs(i, j, node, visited):
+            if '$' in node:
+                result.append(node['$'])
+                del node['$']
+
+            if not (0 <= i < m and 0 <= j < n) or (i, j) in visited:
+                return
+            
+            char = board[i][j]
+            if char not in node:
+                return
+            
+            visited.add((i, j))
+
+            for di, dj in [(0, 1), (1, 0), (0, -1), (-1, 0)]:
+                dfs(i + di, j + dj, node[char], visited)
+
+            visited.remove((i, j))
+
+        m, n = len(board), len(board[0])
+        result = []
+
+        for i in range(m):
+            for j in range(n):
+                dfs(i, j, root, set())
+
+        return result