Update README.md #16

Original file line number	Diff line number	Diff line change
Expand Up		@@ -497,6 +497,17 @@ class Solution:
		from itertools import permutations
		return list(permutations(nums))
		```
	## [48. rotate-image 1行](https://leetcode.com/problems/rotate-image/)
	先转置后镜像对称
	```python
	class Solution:
	def rotate(self, matrix: List[List[int]]) -> None:
	"""
	Do not return anything, modify matrix in-place instead.
	"""
	matrix[:] = [i[::-1] for i in zip(*matrix)]
	```
	加 [:] 才会修改原列表
		## [49. Group Anagrams 1行](https://leetcode.com/problems/group-anagrams/)
		```python
		class Solution:
Expand Down Expand Up		@@ -989,7 +1000,7 @@ class Solution:
		class Solution:
		def singleNumber(self, nums: List[int]) -> int:
		from functools import reduce
	return reduce(int.__xor__, nums)
	return reduce(xor, nums)
		```
		- 这里用到了异或(xor),相同的数字异或后为0,0异或任何数都等于那个数,用reduce在列表所有元素之间使用异或^,那么留下的就是那个单独的数字了
		## [138. Copy List with Random Pointer 1行](https://leetcode.com/problems/copy-list-with-random-pointer/)
Expand Down Expand Up		@@ -1379,7 +1390,7 @@ class Solution:
		return int(bin(n)[2:].zfill(32)[::-1], 2)
		```
		- 字符串操作
	- [ziff用法](https://www.runoob.com/python/att-string-zfill.html)
	- [zfill用法](https://www.runoob.com/python/att-string-zfill.html)
		## [191. Number of 1 Bits 1行](https://leetcode.com/problems/number-of-1-bits/)
		```python
		class Solution(object):
Expand Down Expand Up		@@ -1510,6 +1521,13 @@ class Solution:
		return nums[0]
		return f(r, k - len(l) - len(m))
		```
	```python
	class Solution:
	def findKthLargest(self, nums: List[int], k: int) -> int:
	return nlargest(k,nums)[-1]
	```

	- 用了 heapq 的 nlargest 函数,返回一个 list , 然后取最后一个
		## [217. Contains Duplicate 1行](https://leetcode.com/problems/contains-duplicate/)
		```python
		class Solution:
Expand Down Expand Up		@@ -1765,6 +1783,19 @@ class Solution:
		return False
		```
		- 从矩阵右上角开始,若值比 target 大则证明这一列的值都比 target 大,继续搜索前面的列;若比 target 小说明 target 可能在后面的行中,进入下一行
	## [242. 有效的字母异位词 1行](https://leetcode.com/problems/valid-anagram/)
	```python
	class Solution:
	def isAnagram(self, s: str, t: str) -> bool:
	return Counter(s) == Counter(t)
	```
	- O(n) 思路等于建哈希表
	```python
	class Solution:
	def isAnagram(self, s: str, t: str) -> bool:
	return sorted(s) == sorted(t)
	```
	- O(n log(n)) 排序后相等,原来就相等,利用 python 的 str 可以直接排序的特点
		## [258. Add Digits 1行](https://leetcode.com/problems/add-digits/)
		```python
		class Solution:
Expand Down Expand Up		@@ -2479,6 +2510,14 @@ class Solution:
		def kClosest(self, points: List[List[int]], K: int) -> List[List[int]]:
		return sorted(points, key=lambda x: x[0]2 + x[1]2)[:K]
		```
	## [976. 三角形的最大周长 2行](https://leetcode.com/problems/largest-perimeter-triangle/)
	```python
	class Solution:
	def largestPerimeter(self, A: List[int]) -> int:
	A.sort(reverse=True)
	return next((i+j+k for i,j,k in zip(A,A[1:],A[2:]) if j+k>i ),0)
	```
	- 利用 next 函数返回第一个满足条件的值,不然就返回默认值的特点
		## [1290. Convert Binary Number in a Linked List to Integer](https://leetcode.com/problems/convert-binary-number-in-a-linked-list-to-integer/)
		```python
		# Definition for singly-linked list.
Expand Down

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