The origianl question is as follow.
Given an array S of n integers, find three integers in S such that the sum is closest to a given number, target. Return the sum of the three integers. You may assume that each input would have exactly one solution.
Example:
For example, given array S = {-1 2 1 -4}, and target = 1.
The sum that is closest to the target is 2. (-1 + 2 + 1 = 2).
Method
Use three node moving. The time consuming is N square.
class Solution(object):
def threeSumClosest(self, nums, target):
"""
:type nums: List[int]
:type target: int
:rtype: int
"""
nums.sort()
s,left,right = 0,0,0
res = nums[0] + nums[1] + nums[2]
for i in range(len(nums)-2):
left = i + 1
right = len(nums)-1
while left != right:
s = nums[left] + nums[right] + nums[i]
if s == target:
return s
elif s > target:
if s-target < abs(res-target):
res = s
right -= 1
else:
if target-s < abs(res-target):
res = s
left += 1
return res
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