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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).
https://leetcode.com/problems/3sum-closest/
与3Sum相同的思路http://www.cnblogs.com/Liok3187/p/4540921.html
每一轮先固定一个数，用双指针指向数组的头和尾。
如果目前三个数的和小于target，头指针++，否则尾指针--，直到指针碰到为止，记录最接近的结果。
1 /** 2 * @param {number[]} nums 3 * @param {number} target 4 * @return {number} 5 */ 6 var threeSumClosest = function(nums, target) { 7 var min = Infinity; 8 var res = 0; 9 nums = nums.sort(sorting); 10 11 for(var i = 0; i < nums.length - 2; i++){ 12 if(nums[i - 1] !== undefined && nums[i - 1] === nums[i]){ 13 continue; 14 } 15 var curr = nums[i]; 16 var m = i + 1; 17 var n = nums.length - 1; 18 while(m < n){ 19 var tmp = Math.abs(nums[m] + nums[n] + curr - target); 20 if(tmp < min){ 21 min = tmp; 22 res = nums[m] + nums[n] + curr; 23 } 24 25 if(nums[m] + nums[n] + curr < target){ 26 m++; 27 } else { 28 n--; 29 } 30 } 31 } 32 return res; 33 34 function sorting(a, b){ 35 if(a > b){ 36 return 1; 37 }else if(a < b){ 38 return -1; 39 }else{ 40 return 0; 41 } 42 } 43 };
[LeetCode][JavaScript]3Sum Closest
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原文地址：http://www.cnblogs.com/Liok3187/p/4609057.html
