Brush question 3

7、 subject ： Write a function to find the longest common prefix in the string array . If no common prefix exists , Returns an empty string .
Example ：

explain ： All inputs contain only lowercase letters a-z.

class Solution(object):
def longestCommonPrefix(self, strs):
if not strs:
return “”
for i in range(len(strs[0])):
for string in strs[1:]:
if i >= len(string) or string[i] != strs[0][i]:
return strs[0][:i]
return strs[0]
8、 The sum of three numbers
class Solution(object):
def threeSum(self, nums):
res = []
nums.sort()
n=len(nums)
for i in range(n-2):
if i0 or nums[i]>nums[i-1]:
left,right = i+1,n-1
while left<right:
ident = nums[i]+nums[left]+nums[right]
if ident0:
res.append([nums[i],nums[left],nums[right]])
left+=1
right-=1
while left<right and nums[left]==nums[left-1]:
left+=1
while left<right and nums[right]==nums[right+1]:
right-=1
elif ident<0:
left+=1
else:
right-=1
return res

9、 Container for the most water
class Solution:
def maxArea(self, height):
l = 0
r = len(height) - 1
s = 0
while l < r:
s = max( (r-l)*min(height[l], height[r]), s)
if height[l] > height[r]:
r -= 1
else:
l += 1
return s