2019-11-13

Author: JiayangWu

0392.判断子序列/0392-判断子序列.py

@@ -0,0 +1,13 @@
+class Solution(object):
+    def isSubsequence(self, s, t):
+        """
+        :type s: str
+        :type t: str
+        :rtype: bool
+        """
+        i, j = 0, 0
+        while i < len(s) and j < len(t):
+            if s[i] == t[j]:
+                i += 1
+            j += 1
+        return i == len(s)

0477.汉明距离总和/0477-汉明距离总和.py

@@ -0,0 +1,20 @@
+class Solution(object):
+    def totalHammingDistance(self, nums):
+        """
+        :type nums: List[int]
+        :rtype: int
+        """
+        if not nums:
+            return 0
+        res = 0
+        mask = 1
+        for i in range(32):
+            cnt_one = 0
+            for num in nums:
+                cnt_one += 1 if num & mask else 0 
+                
+            res += cnt_one * (len(nums) - cnt_one)
+            mask = mask << 1
+        return res
+        
+                

0543.二叉树的直径/0543-二叉树的直径.py

@@ -0,0 +1,26 @@
+# 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 diameterOfBinaryTree(self, root):
+        """
+        :type root: TreeNode
+        :rtype: int
+        """
+        if not root:
+            return 0
+        self.res = 0
+        def height(node):
+            if not node:
+                return 0
+            left_h = height(node.left)
+            right_h = height(node.right)
+            
+            self.res = max(self.res, left_h + right_h) 
+            return 1 + max(left_h, right_h)
+        height(root)
+        return self.res

0646.最长数对链/0646-最长数对链.py

@@ -0,0 +1,16 @@
+class Solution(object):
+    def findLongestChain(self, pairs):
+        """
+        :type pairs: List[List[int]]
+        :rtype: int
+        """
+        pairs = sorted(pairs, key = lambda x: x[1])
+        
+        end = pairs[0][0] - 1
+        res = 0
+        for pair in pairs:
+            if pair[0] > end:
+                res += 1
+                end = pair[1]
+        
+        return res

0792.匹配子序列的单词数/0792-匹配子序列的单词数.py

@@ -0,0 +1,31 @@
+class Solution(object):
+    def numMatchingSubseq(self, S, words):
+        """
+        :type S: str
+        :type words: List[str]
+        :rtype: int
+        """
+        from collections import defaultdict
+        
+        dic = defaultdict(list)
+        for i, ch in enumerate(S):
+            dic[ch].append(i)
+            
+        res = 0
+        for word in words:
+            pre = -1
+            flag = True
+            for i, ch in enumerate(word):
+                l = dic[ch]
+                # 在l找第一个比pre大的元素
+                idx = bisect.bisect(l, pre)
+                
+                if idx == len(l):# 没找到
+                    flag = False
+                    break
+                pre = l[idx]
+                
+            if flag:
+                res += 1
+
+        return res

1180.统计只含单一字母的子串/1180-统计只含单一字母的子串.py

@@ -0,0 +1,14 @@
+class Solution(object):
+    def countLetters(self, S):
+        """
+        :type S: str
+        :rtype: int
+        """
+        res = 0
+        for i in range(len(S)):
+            for j in range(i + 1, len(S) + 1):
+                substring = S[i:j]
+                if substring == substring[0] * len(substring):
+                    res += 1
+                    # print substring
+        return res

1207.独一无二的出现次数/1207-独一无二的出现次数.py

@@ -0,0 +1,8 @@
+class Solution(object):
+    def uniqueOccurrences(self, arr):
+        """
+        :type arr: List[int]
+        :rtype: bool
+        """
+        d = collections.Counter(arr)
+        return len(d.values()) == len(set(d.values()))

1213.三个有序数组的交集/1213-三个有序数组的交集.py

@@ -0,0 +1,18 @@
+class Solution(object):
+    def arraysIntersection(self, arr1, arr2, arr3):
+        """
+        :type arr1: List[int]
+        :type arr2: List[int]
+        :type arr3: List[int]
+        :rtype: List[int]
+        """
+        res = []
+        record = [0 for _ in range(2005)]
+        for num in arr1 + arr2 + arr3:
+            record[num] += 1
+        
+        for i in range(len(record)):
+            if record[i] == 3:
+                res.append(i)
+                
+        return res

1221.分割平衡字符串/1221-分割平衡字符串.py

@@ -0,0 +1,21 @@
+class Solution(object):
+    def balancedStringSplit(self, s):
+        """
+        :type s: str
+        :rtype: int
+        """
+        if not s:
+            return 0
+        # print s
+        l, r = 0, 0
+        
+        for i in range(len(s)):
+            if s[i] == "R":
+                r += 1
+            else:
+                l += 1
+            # print r, l
+            if l == r:
+                return 1 + self.balancedStringSplit(s[i + 1:])
+            
+        return 0

1232.缀点成线/1232-缀点成线.py

@@ -0,0 +1,22 @@
+class Solution(object):
+    def checkStraightLine(self, coordinates):
+        """
+        :type coordinates: List[List[int]]
+        :rtype: bool
+        """
+        c = sorted(coordinates, key = lambda x:x[0])
+        k = None
+        for i in range(len(c)):
+            if i:
+                x0, y0 = c[i - 1][0], c[i - 1][1]
+                x1, y1 = c[i][0], c[i][1]
+            
+                if x0 == x1:
+                    return False
+                new_k = 1.0 * (y1 - y0) / (x1 - x0)
+                if k and k != new_k:
+                    return False
+                k = new_k
+            
+        return True
+