3Sum Closest

<-M 16> 3Sum Closest

class Solution {
public:
    int threeSumClosest(vector<int>& nums, int target) {
        sort(nums.begin(), nums.end());
        int n = nums.size();

        int ans = INT_MAX, min_diff = INT_MAX;
        for (int i = 0; i < n; i++) {
            int target_temp = target - nums[i];

            int j = i + 1, k = nums.size() - 1;
            while (j < k) {
                int sum = nums[i] + nums[j] + nums[k];
                int diff = abs(target_temp - nums[j] - nums[k]);
                if (nums[j] + nums[k] <= target_temp) {
                    if (min_diff > diff) {
                        min_diff = diff;
                        ans = sum;
                    }
                    j++;
                }
                else if (nums[j] + nums[k] > target_temp) {
                    if (min_diff > diff) {
                        min_diff = diff;
                        ans = sum;
                    }
                    k--;
                }
            }
        }
        return ans;
    }
};