最接近的三数之和

代码

public class Solution {
    /**
     * @param numbers: Give an array numbers of n integer
     * @param target: An integer
     * @return: return the sum of the three integers, the sum closest target.
     */
    public int threeSumClosest(int[] numbers, int target) {
        // write your code here
        if(numbers==null||numbers.length<=0){
            return 0;
        }
        Arrays.sort(numbers);
        int ans = Integer.MAX_VALUE;
        for(int i=0; i<numbers.length; i++){
            for(int j=i+1, k=numbers.length-1; j<k;){
                int sum = numbers[i]+numbers[j]+numbers[k];
                // update the closest answer
                ans = (Math.abs(target-sum)<Math.abs(target-ans) ? sum:ans);
                if (sum > target) --k;
                else if (sum < target) ++j;
                else return sum;    // sum equal to target
            }
        }
        return ans;
    }
}