Leetcode#16 3Sum Cloest

class Solution {
    public:
        int threeSumClosest(vector<int>& nums, int target) {
            if (nums.size() < 3)
                return 0;

            sort(nums.begin(), nums.end());

            int gap = INT_MAX;
            for(int i=0; i<nums.size(); i++) {
                if (i>0 && nums[i] == nums[i-1])
                    continue;

                int tmp = target - nums[i];
                int left = i+1;
                int right = nums.size()-1;

                while (left < right) {
                    int diff = tmp - (nums[left] + nums[right]);
                    if (abs(diff) < abs(gap)) {
                        gap = diff;
                    }
                    if(diff == 0) {
                        return target;
                    } else {
                        if (diff < 0) {
                            right--;
                        } else {
                            left++;
                        }
                    }
                }
            }
            return target - gap;
        }
};