1.从排序数组中删除重复项
class Solution(object):
def removeDuplicates(self, nums):
"""
:type nums: List[int]
:rtype: int
"""
length=len(nums)
if length==0:
return 0
i=0
for j in range(1,length):
if nums[j]!=nums[i]:
i+=1
nums[i]=nums[j]
return i+1
2.买卖股票的最佳时机 II
class Solution(object):
def maxProfit(self, prices):
"""
:type prices: List[int]
:rtype: int
""''
profit = 0
for i in range(1,len(prices)):
if prices[i] > prices[i-1]:
profit += prices[i]-prices[i-1]
return profit
3.给定一个数组，将数组中的元素向右移动 k 个位置，其中 k 是非负数
思路1
class Solution(object):
def rotate(self, nums, k):
"""
:type nums: List[int]
:type k: int
:rtype: None Do not return anything, modify nums in-place instead.
"""
i=0
j=0
length=len(nums)
while i<k:
n=nums[-1]
for j in range(0,length-1):
nums[len(nums)-j-1]=nums[len(nums)-j-2]
nums[0]=n
i=i+1
return nums
思路2
class Solution:
def rotate(self, nums, k):
nums_len = len(nums)
nums[:] = nums[nums_len - k :] + nums[:nums_len - k] #数组切片可以直接加减，放在一起
print(nums)
4.存在重复
class Solution(object):
def containsDuplicate(self, nums):
"""
:type nums: List[int]
:rtype: bool
"""
dict = {}
for i in nums:
if dict.get(i):
return True
dict[i] = 1
return False
5.只出现一次的数字
这个想法是看别人的，精彩。
class Solution(object):
def singleNumber(self, nums):
"""
:type nums: List[int]
:rtype: int
"""
result = 0
for num in nums:
result = result ^ num
return result