(practice C language every day) the sum of the nearest three numbers

The closest sum of three

Given an include  n  Array of integers  nums  and A target value  target. find  nums  Three integers in , Make their sum and  target  Nearest . Returns the sum of the three numbers . Assume that there is only one answer for each group of input .

Example ：

 Input ：nums = [-1,2,1,-4], target = 1
 Output ：2
 explain ： And  target  The closest and  2 (-1 + 2 + 1 = 2) .

Tips ：

• 3 <= nums.length <= 10^3
• -10^3 <= nums[i] <= 10^3
• -10^4 <= target <= 10^4

The following program realizes this function ：

#include <cstdlib>
class Solution
{
public:
	int threeSumClosest(vector<int> &nums, int target)
	{
		sort(nums.begin(), nums.end());
		int cur, left, right;
		cur = 0;
		int closest = nums[0] + nums[1] + nums[2];
		while (cur < nums.size() - 2)
		{
			left = cur + 1;
			right = nums.size() - 1;
			int n;
			while (left < right)
			{
				n = nums[cur] + nums[left] + nums[right];
				if (abs(target - n) < abs(target - closest))
				{
					closest = n;
				}
				if (n == target)
				{
					break;
				}
				else if (n > target)
                {
                	int t = right - 1;
                	while (t > left && nums[t] == nums[right])
	                	t--;
	                right = t;
                }
				else
				{
					int t = left + 1;
					while (t < right && nums[t] == nums[left])
						t++;
					left = t;
				}
			}
			int t = cur + 1;
			while (t < nums.size() && nums[t] == nums[cur])
				t++;
			cur = t;
		}
		return closest;
	}
};