给定一个整数数组和一个目标值,找出数组中和为目标值的两个数。
你可以假设每个输入只对应一种答案,且同样的元素不能被重复利用。
示例:
给定 nums = [2, 7, 11, 15], target = 9
因为 nums[0] + nums[1] = 2 + 7 = 9
所以返回 [0, 1]
解法一:
class Solution:
def twoSum(self, nums, target):
"""
:type nums: List[int]
:type target: int
:rtype: List[int]
"""
result=[0,0]
len_nums=len(nums)
for i in range(len_nums):
for j in range(i+1,len_nums):
if nums[j]==target-nums[i]:
result=[i,j]
break
else:
continue
if result!=[0,0]:
return result[0],result[1]
解法二:
class Solution:
def twoSum(self, nums, target):
"""
:type nums: List[int]
:type target: int
:rtype: List[int]
"""
len_nums=len(nums)
for i in range(len_nums):
left=target-nums[i]
if left in nums:
index_of_left=nums.index(left)
if i!=index_of_left:
return i,index_of_left
解法三:
class Solution:
def twoSum(self, nums, target):
"""
:type nums: List[int]
:type target: int
:rtype: List[int]
"""
len_nums=len(nums)
left_dic={}
for i in range(len_nums):
left=target-nums[i]
if nums[i] in left_dic:
return left_dic[nums[i]],i
else:
left_dic[left]=i