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).
同 Leetcode 15 3Sum ，增加一个target维护最靠近的值。
def three_sum_closest(nums, target) ans = nums[0] + nums[1] + nums[2] a = nums.sort a.length.times do |i| j, k = i+1, a.length - 1 while j < k sum = a[i] + a[j] + a[k] return sum if sum == target ans = sum if (target-sum).abs < (target-ans).abs if sum < target j += 1 elsif sum > target k -= 1 end end end ans end
原文：http://www.cnblogs.com/lilixu/p/4575539.html