016.三数之和最近.py

class Solution(object):
    def threeSumClosest(self, nums, target):
        """
        :type nums: List[int]
        :type target: int
        :rtype: int
        """
        # O(n^2) and O(1)
        nums.sort()
        result = nums[0] + nums[1] + nums[2]
        for i in range(len(nums) - 2):
            j, k = i+1, len(nums) - 1
            while j < k:
                sum = nums[i] + nums[j] + nums[k]
                if sum == target:
                    return sum
                if abs(sum - target) < abs(result - target):
                    result = sum
                if sum < target:
                    j += 1
                elif sum > target:
                    k -= 1
        return result