Easy.
# 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].
class Solution():
def twoSum(self, nums, target):
d = {}
for i, v in enumerate(nums):
if v in d:
return [d[v], i]
d[target - v] = i
if __name__ == '__main__':
assert Solution().twoSum([2, 7, 11, 15], 22) == [1, 3]