2019-11-24

Author: JiayangWu

0386.字典序排数/0386-字典序排数.py

@@ -0,0 +1,20 @@
+class Solution(object):
+    def lexicalOrder(self, n):
+        """
+        :type n: int
+        :rtype: List[int]
+        """
+        return sorted(range(1, n + 1), key = str)
+#         res = []
+       
+#         def dfs(k):
+#             if k > n:
+#                 return
+#             res.append(k)
+            
+#             for i in range(10):
+#                 dfs(10 * k + i)
+        
+#         for i in range(1, 10):
+#             dfs(i)
+#         return res

1161.最大层内元素和/1161-最大层内元素和.py

@@ -0,0 +1,33 @@
+# Definition for a binary tree node.
+# class TreeNode(object):
+#     def __init__(self, x):
+#         self.val = x
+#         self.left = None
+#         self.right = None
+
+class Solution(object):
+    def maxLevelSum(self, root):
+        """
+        :type root: TreeNode
+        :rtype: int
+        """
+        from collections import deque
+        queue = deque([root])
+        
+        layer = 1
+        res = 1
+        max_values = 0
+        while queue:
+            values = 0
+            for _ in range(len(queue)):
+                node = queue.popleft()
+                if node:
+                    values += node.val
+                    queue.append(node.left)
+                    queue.append(node.right)
+            if values > max_values:
+                max_values = values
+                res = layer
+            layer += 1
+        return res
+                    

1196.最多可以买到的苹果数量/1196-最多可以买到的苹果数量.py

@@ -0,0 +1,13 @@
+class Solution(object):
+    def maxNumberOfApples(self, arr):
+        """
+        :type arr: List[int]
+        :rtype: int
+        """
+        arr.sort()
+        s = 0
+        for i, num in enumerate(arr):
+            if s + num > 5000:
+                return i
+            s += num
+        return len(arr)

1198.找出所有行中最小公共元素/1198-找出所有行中最小公共元素.py

@@ -0,0 +1,13 @@
+class Solution(object):
+    def smallestCommonElement(self, mat):
+        """
+        :type mat: List[List[int]]
+        :rtype: int
+        """
+        from collections import Counter
+        flatten = sum(mat,[])  
+        dic = Counter(flatten)
+        for num in mat[0]:
+            if dic[num] == len(mat):
+                return num
+        return -1

1266.访问所有点的最小时间/1266-访问所有点的最小时间.py

@@ -0,0 +1,18 @@
+class Solution(object):
+    def minTimeToVisitAllPoints(self, points):
+        """
+        :type points: List[List[int]]
+        :rtype: int
+        """
+        def helper(pair1, pair2):
+            x0, y0 = pair1[0], pair1[1]
+            x1, y1 = pair2[0], pair2[1]
+            
+            return max(abs(y1 - y0), abs(x1 - x0))
+        
+        res = 0
+        for i, point in enumerate(points):
+            if i > 0:
+                res += helper(point, points[i - 1])
+                
+        return res

1267.统计参与通信的服务器/1267-统计参与通信的服务器.py

@@ -0,0 +1,29 @@
+class Solution(object):
+    def countServers(self, grid):
+        """
+        :type grid: List[List[int]]
+        :rtype: int
+        """
+        
+        m, n = len(grid), len(grid[0])
+        res = 0
+        for i in range(m):
+            for j in range(n):
+                if grid[i][j] == 1:
+                    # horizontal
+                    for col in range(n):
+                        if col != j:
+                            if grid[i][col] in [1, 2]:
+                                grid[i][j] = 2
+                                grid[i][col] = 2
+                    
+                    # vertical
+                    for row in range(m):
+                        if row != i:
+                            if grid[row][j] in [1, 2]:
+                                grid[i][j] = 2
+                                grid[row][j] = 2
+                if grid[i][j] == 2:
+                    res += 1
+        # print grid
+        return res

1268.搜索推荐系统/1268-搜索推荐系统.py

@@ -0,0 +1,21 @@
+class Solution(object):
+    def suggestedProducts(self, products, searchWord):
+        """
+        :type products: List[str]
+        :type searchWord: str
+        :rtype: List[List[str]]
+        """
+        products.sort()
+        res = []
+        prefix = ""
+        for char in searchWord:
+            tmp = []
+            prefix += char
+            idx = bisect.bisect_left(products, prefix) # 找当前prefix 起点，因为有序所以二分
+            for word in products[idx:]:
+                if len(tmp) >= 3 or word[:len(prefix)] > prefix:
+                    break
+                if word[:len(prefix)] == prefix:
+                    tmp.append(word)
+            res.append(tmp)
+        return res

1269.停在原地的方案数/1269-停在原地的方案数.py

@@ -0,0 +1,23 @@
+class Solution(object):
+    def numWays(self, steps, arrLen):
+        """
+        :type steps: int
+        :type arrLen: int
+        :rtype: int
+        """
+        # dp[i][j] 代表走 i 步，到位置 j 的解
+        # dp[i][j] = dp[i - 1][j - 1] + dp[i - 1][j] + dp[i - 1][j + 1]
+        n = min(steps, arrLen)
+        dp = [[0 for _ in range(n)] for _ in range(steps + 1)]
+        mod = 10 ** 9 + 7
+        
+        dp[0][0] = 1
+        for i in range(1, steps + 1):
+            for j in range(n):
+                if j == 0:
+                    dp[i][j] += (dp[i - 1][0] + dp[i - 1][1]) % mod
+                elif j == n - 1:
+                    dp[i][j] += (dp[i - 1][j] + dp[i - 1][j - 1]) % mod
+                else:
+                    dp[i][j] += (dp[i - 1][j - 1] + dp[i - 1][j] + dp[i - 1][j + 1])  % mod                         
+        return dp[steps][0]