t9

题目：

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Given an array nums of n integers and an integer target, find three integers in nums such that the sum is closest to target. Return the sum of the three integers. You may assume that each input would have exactly one solution.

Example:

Given array nums = [-1, 2, 1, -4], and target = 1.

The sum that is closest to the target is 2. (-1 + 2 + 1 = 2).

代码：

 1 class Solution:
 2     def threeSumClosest(self, nums: List[int], target: int) -> int:
 3         closestTemp = float('inf')
 4         nums.sort()
 5         
 6         for p_i in range(len(nums)-2):
 7             if(p_i > 0 and nums[p_i] == nums[p_i-1]):
 8                 continue
 9             p_r = len(nums) -1
10             p_l = p_i + 1
11             while(p_l < p_r):
12                 three_sum = nums[p_i] + nums[p_l] + nums[p_r]
13                 if(abs(target - three_sum) < abs(target-closestTemp)):
14                         closestTemp = three_sum
15                         #print("new: ", closestTemp)
16                 if(three_sum == target):
17                     return three_sum
18                 elif(three_sum < target):
19                     p_l+=1
20                     while(p_l < p_r and nums[p_l] == nums[p_l-1]):
21                         p_l+=1
22                 elif(three_sum > target):
23                     p_r-=1
24                     while(p_l < p_r and nums[p_r] == nums[p_r+1]):
25                         p_r-=1
26                     
27         return closestTemp