Leetcode-016-最接近的三数之和

先排序，然后双指针。

class Solution {
    public int threeSumClosest(int[] nums, int target) {
        int res = nums[0]+nums[1]+nums[2];
        Arrays.sort(nums);

        for(int i=0;i<nums.length;i++){

            int start = i+1;
            int end = nums.length-1;

            while(start < end){
                int num_sum = nums[i]+nums[start]+nums[end];
                if(Math.abs(num_sum-target)<Math.abs(res-target)){
                    res = num_sum;

                }
                if(num_sum<target){
                    start++;
                }else if(num_sum>target){
                    end--;
                }else{
                    return num_sum;
                }
            }
        }
        return res;
    }
}

class Solution:
    def threeSumClosest(self, nums: List[int], target: int) -> int:
        nums.sort()
        res = nums[0]+nums[1]+nums[2]

        for i in range(len(nums)):
            start = i+1
            end = len(nums)-1
            while start < end:
                num_sum = nums[i] + nums[start] + nums[end]
                if abs(num_sum-target) < abs(res-target):
                    res = num_sum
                if num_sum < target:
                    start+=1
                elif num_sum > target:
                    end-=1
                else:
                    return res
        return res