2019-07-26

Author: JiayangWu

0211.添加与搜索单词-数据结构设计/0211-添加与搜索单词-数据结构设计.py

@@ -1,11 +1,11 @@
 class WordDictionary(object):
-
+ 
     def __init__(self):
         """
         Initialize your data structure here.
         """
         self.roots = {}
-
+ 
     def addWord(self, word):
         """
         Adds a word into the data structure.
@@ -17,7 +17,7 @@ def addWord(self, word):
         for char in word:
             node = node.setdefault(char, {})
         node["end"] = True
-
+ 
     def search(self, word):
         """
         Returns if the word is in the data structure. A word could contain the dot character '.' to represent any one letter.
@@ -27,7 +27,7 @@ def search(self, word):
         self.res = False
         self.searchHelper(self.roots, word)
         return self.res
-
+ 
     def searchHelper(self, dic, word):
         if not word:
             self.res |= "end" in dic

0212.单词搜索II/0212-单词搜索II.py

@@ -59,10 +59,10 @@ def findWords(self, board, words):
         for word in words:
             tree.insert(word)
         words = set(words)
+        
         res = set()
         def dfs(x0, y0, node, tmpword):
             visited.add((x0, y0))
-            # print tmpword, x0, y0
             for k in range(4):
                 x = x0 + dx[k]
                 y = y0 + dy[k]
@@ -72,8 +72,8 @@ def dfs(x0, y0, node, tmpword):
                     dfs(x, y, node[board[x][y]], tmpword + board[x][y])
                     visited.remove((x,y))
 
-            if tmpword in words:
-                res.add(tmpword)
+            if tmpword in words: #找到一个单词了
+                res.add(tmpword) #用集合避免重复
 
         for i in range(m):
             for j in range(n):

0213.打家劫舍II/0213-打家劫舍II.py

@@ -0,0 +1,26 @@
+class Solution(object):
+    def rob(self, nums):
+        """
+        :type nums: List[int]
+        :rtype: int
+        """
+        if len(nums) == 1:
+            return nums[0]
+        return max(self.rob2(nums[1:]), self.rob2(nums[:-1]))
+    
+    def rob2(self, nums):
+        """
+        :type nums: List[int]
+        :rtype: int
+        """
+        # return 0
+        if not nums:
+            return 0
+        dp = [0 for _ in nums]
+        dp[0] = nums[0] 
+        for i in range(1, len(nums)):
+            if i == 1:
+                dp[i] = max(dp[0], nums[i])
+            else:
+                dp[i] = max(dp[i - 2] + nums[i], dp[i - 1])
+        return dp[-1]