2019-09-06

Author: JiayangWu

0286.墙与门/0286-墙与门.py

@@ -0,0 +1,32 @@
+class Solution(object):
+    def wallsAndGates(self, rooms):
+        """
+        :type rooms: List[List[int]]
+        :rtype: None Do not return anything, modify rooms in-place instead.
+        """
+        from collections import deque
+        if not rooms or not rooms[0]:
+            return rooms
+        m, n = len(rooms), len(rooms[0])
+        dx = [1, -1, 0, 0]
+        dy = [0, 0, 1, -1]
+        INF = 2147483647
+        queue = deque()
+        def bfs(queue):
+            while queue:
+                pos = queue.popleft()
+                x0, y0 = pos
+                    
+                for k in range(4):
+                    x = x0 + dx[k]
+                    y = y0 + dy[k]
+                    if 0 <= x < m and 0 <= y < n and rooms[x][y] == INF:
+                        rooms[x][y] = rooms[x0][y0] + 1
+                        queue.append((x, y))
+                
+        for i in range(m):
+            for j in range(n):
+                if rooms[i][j] == 0: #ÏÖÔÚ´ÓÿÉÈÃųö·¢
+                    queue.append((i, j))
+        bfs(queue)
+        return rooms

0287.寻找重复数/0287-寻找重复数.py

@@ -4,17 +4,13 @@ def findDuplicate(self, nums):
         :type nums: List[int]
         :rtype: int
         """
-
         slow, fast = 0, 0
-        while(1):
+        while 1:
             slow = nums[slow]
             fast = nums[nums[fast]]
-            # print slow, fast
-            if slow == fast: # loop exists
+            if slow == fast:
                 fast = 0
-                while(nums[slow] != nums[fast]):
+                while nums[slow] != nums[fast]:
                     slow = nums[slow]
                     fast = nums[fast]
-                    # print slow, fast
-                return nums[fast]
-            
+                return nums[fast]

0288.单词的唯一缩写/0288-单词的唯一缩写.py

@@ -0,0 +1,30 @@
+class ValidWordAbbr(object):
+
+    def __init__(self, dictionary):
+        """
+        :type dictionary: List[str]
+        """
+        from collections import defaultdict
+        self.dic = defaultdict(list)
+        for word in dictionary:
+            if len(word) <= 2:
+                self.dic[word].append(word)
+            else:
+                self.dic[word[0] + str(len(word) - 2) + word[-1]].append(word)
+
+    def isUnique(self, word):
+        """
+        :type word: str
+        :rtype: bool
+        """
+        if len(word) <= 2:
+            return not self.dic[word] or self.dic[word] == [word] * len(self.dic[word])
+        else:
+            s = word[0] + str(len(word) - 2) + word[-1]
+            return  not self.dic[s] or self.dic[s] == [word] * len(self.dic[s])
+        
+
+
+# Your ValidWordAbbr object will be instantiated and called as such:
+# obj = ValidWordAbbr(dictionary)
+# param_1 = obj.isUnique(word)

0289.生命游戏/0289-生命游戏.py

@@ -2,52 +2,36 @@ class Solution(object):
     def gameOfLife(self, board):
         """
         :type board: List[List[int]]
-        :rtype: void Do not return anything, modify board in-place instead.
+        :rtype: None Do not return anything, modify board in-place instead.
         """
-        m = len(board)
-        if m == 0:
-            return board
-        n = len(board[0])
-        if n == 0:
-            return board
+        if not board or not board[0]:
+            return
+        m, n = len(board), len(board[0])
+        dx = [1, -1, 0, 0, 1, 1, -1, -1]
+        dy = [0, 0, 1, -1, 1, -1, 1, -1]
 
-        alivex = list()
-        alivey = list()
-        
-        def neibor(x, y): #统计八个邻居里有几个是活细胞（1）
-            dx = [1, -1, 0, 0, 1, -1, -1, 1]
-            dy = [0, 0, 1, -1, 1, -1, 1, -1]
-            
+        def countLiveCells(x0, y0):
             cnt = 0
             for k in range(8):
-                xx = x + dx[k]
-                yy = y + dy[k]
+                x = x0 + dx[k]  
+                y = y0 + dy[k] 
+                
+                if 0 <= x < m and 0 <= y < n and board[x][y] == 1:
+                    cnt += 1
 
-                if 0 <= xx < m and 0 <= yy < n and board[xx][yy] == 1:
-                    cnt += 1 
-                        
             return cnt
 
-        
+        liveCellSet = set()
         for i in range(m):
             for j in range(n):
-                cnt = neibor(i, j)
-                # print i, j, cnt
-                if (board[i][j] == 1 and 2 <= cnt <= 3) or (board[i][j] == 0 and cnt == 3):
-                        alivex.append(i)
-                        alivey.append(j)
-        
-        alivecnt = 0
+                if board[i][j] == 1 and countLiveCells(i, j) in [2, 3]:
+                    liveCellSet.add((i, j))
+                elif board[i][j] == 0 and countLiveCells(i, j) == 3:
+                    liveCellSet.add((i, j))
+                    
         for i in range(m):
             for j in range(n):
-                board[i][j] = 0
-                
-                if alivecnt < len(alivex):
-                    if alivex[alivecnt] == i and alivey[alivecnt] == j:
-                        board[i][j] = 1
-                        alivecnt += 1
-                        
-        return board
-                    
-                        
-                        
+                if (i, j) in liveCellSet:
+                    board[i][j] = 1
+                else:
+                    board[i][j] = 0