21.03.16 LeetCode16. 最接近的三数之和

class Solution {
    public int threeSumClosest(int[] nums, int target) {
        int n = nums.length;
        int closest = 100000;
        Arrays.sort(nums);
        for(int i = 0;i<n-2;i++)
        {
            if(i>0 && nums[i] == nums[i-1])
                continue;
            int left = i+1,right = n-1;
            while(left<right)
            {
                int sum = nums[i]+nums[left]+nums[right];
                if(sum == target)
                    return sum;
                //更新差值
                if( Math.abs(sum-target) < Math.abs(closest-target) )
                    closest = sum;
                //移动指针
                if(sum > target)
                {
                    while(left<right && nums[right]==nums[right-1] )
                        right--;
                    right--;
                }
                else{
                    while(left < right && nums[left] == nums[left+1])
                        left++;
                    left++;
                }
                
            }
        }
        return closest;
    }
}