Given an array of integers, return indices of the two numbers such that they add up to a specific target.
You may assume that each input would have exactly one solution, and you may not use the same element twice.
Example:
Given nums = [2, 7, 11, 15], target = 9,
Because nums[0] + nums[1] = 2 + 7 = 9,
return [0, 1]
- 方法一：时间复杂度O(n*n)
class solution(object):
def twosum(self,nums,target):
b =False
i =0
j =len(nums)-1
while j>0:
while i
if not nums[i]+nums[j]==target :
i +=1
else :
b=True
print( i+1,j+1)
break
j-=1
if not b:
print("null")
sl=solution()
sl.twosum([1,3,7,8],10)
class Solution(object):
"""
:type nums: List[int]
:type target: int
:rtype: List[int]
"""
def twosum(self,nums,target):
b= False
d ={}
size = 0
print(nums)
while size < len(nums):
if not int(nums[size]) in d:
d[int(nums[size])]=size+1
if target - int(nums[size]) in d:
if d[target - int(nums[size])] < size+1:
b = True
ans = [d[target-int(nums[size])], size+1]
print(ans)
size +=1
if not b:
print("null")
sl=Solution()
sl.twosum(nums=list(input("Please input a list: ")),target=int(input('And input a target:')))
- 笔记：
- len(nums): nums中键值对的数量
- dictionary:字典的增删改(http://www.runoob.com/python/python-dictionary.html),
键必须是唯一的，但值则不必。
值可以取任何数据类型，但键必须是不可变的，如字符串，数字或元组
向字典添加新内容的方法是增加新的键/值对，修改或删除已有键/值对如下实例:
实例
dict = {'Name': 'Zara', 'Age': 7, 'Class': 'First'};
dict['Age'] = 8; # update existing entry
dict['School'] = "DPS School"; # Add new entry
print "dict['Age']: ", dict['Age'];
print "dict['School']: ", dict['School'];
- boolean:定义一个boolean变量,默认为false,在其他条件中定义为ture
