16. 3Sum Closest

class Solution {
    public int threeSumClosest(int[] nums, int target) {
        int n = nums.length;
        int res = 0;
        int m = Integer.MAX_VALUE;
        Arrays.sort(nums);
        for (int i = 0; i < n - 2; i++){
            if (i > 0 && nums[i-1] == nums[i]){
                continue;
            }
            if (nums[i] * 3 >= target){
                int s = nums[i] + nums[i+1] + nums[i+2];
                if (s - target < m){
                    return s;
                }
                break;
            }
            int t = nums[i] + nums[n-1] + nums[n-2];
            if (t == target){
                return t;
            }
            if (t < target){
                if (t - target < m){
                    m = target - t;
                    res = t;
                }
                continue;
            }
            int a = i + 1;
            int b = n - 1;
            while (a < b){
                t = nums[i] + nums[a] + nums[b];
                if (t == target){
                    return t;
                }
                if (Math.abs(t - target) < m){
                    res = t;
                    m = Math.abs(t - target);
                }
                if (t > target){
                    b--;
                } else {
                    a++;
                }
            }
        }
        return res;
    }
}