[Leetcode][016] 3Sum Closest (Java)

题目: https://leetcode.com/problems/3sum-closest/

【标签】Array; Two Pointers

【个人分析】

　　这道题和它的姊妹题 3Sum 非常类似， 就不再多说了，具体一些的分析可以参考 [Leetcode][015] 3Sum

 public class Solution {
     public int threeSumClosest(int[] nums, int target) {
         int result = target;
         int len = nums.length;
         if (len < 3) {
             return 0;
         }
         Arrays.sort(nums);
         for (int i = 0; i < len; i++) {
             int number = nums[i];

             int leftIndex = i + 1;
             int rightIndex = len - 1;
             while (leftIndex < rightIndex) {
                 int threeSum = number + nums[leftIndex] + nums[rightIndex];
                 if (threeSum == target) {
                     // best result found!
                     return target;
                 } else {
                     // update global result
                     if ( result == target ||
                             Math.abs(target - threeSum) < Math.abs(target - result)) {
                         result = threeSum;
                     }
                     if (threeSum < target) {
                         while (leftIndex < rightIndex &&
                                 nums[leftIndex] == nums[leftIndex + 1]) {
                             leftIndex++;
                         }
                         leftIndex++;
                     } else {
                         while (leftIndex < rightIndex &&
                                 nums[rightIndex] == nums[rightIndex - 1]) {
                             rightIndex--;
                         }
                         rightIndex--;
                     }
                 }
             }
         }
         return result;
     }

 }