[LeetCode-Java]16. 3Sum Closest

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).

解：本质和3sum同。

 public int threeSumClosest(int[] nums, int target) {        int len = nums.length;        int closestDist = Integer.MAX_VALUE;        int result = 0;        Arrays.sort(nums);        for (int i = 0;i<len-2;i++){            int begin = i+1;            int end = len - 1;            while (begin<end){                int sum = nums[begin]+nums[end]+nums[i];                if (sum > target){                    if (sum - target < closestDist) {                        closestDist = sum - target;                        result = sum;                    }                    end--;                }else if (sum < target){                    if (target -sum <closestDist) {                        closestDist = target - sum;                        result = sum;                    }                    begin++;                }else {                    return target;                }            }        }        return result;    }