| 标题： | 3Sum Closest |
| 通过率： | 27.0% |
| 难度： | 中等 |
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.
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).
本题是3sum的变形，每次加一个趋近判断即可，代码如下：
1 class Solution: 2 # @return an integer 3 def threeSumClosest(self, num, target): 4 num.sort() 5 ans =9999999 6 for i in range(0, len(num)): 7 l, r = i + 1, len(num) - 1 8 while l < r: 9 sum = num[i] + num[l] + num[r] 10 if abs(sum-target) < abs(ans-target): 11 ans=sum 12 if sum > target: r-=1 13 else :l+=1 14 return ans 15 16
原文：http://www.cnblogs.com/pkuYang/p/4403426.html