leetcode 167. 两数之和 II - 输入有序数组

java: 

class Solution {
    public int[] twoSum(int[] numbers, int target) {
        if(numbers == null){
            return null;
        }
        int i = 0, j = numbers.length - 1;
        while(i < j){
            int sum = numbers[i] + numbers[j];
            if(sum == target){
                return new int[]{i+1,j+1};
            }else if(sum < target){
                i ++;
            }else{
                j--;
            }
        }
        return null;
    }
}