自然数之和（leetcode 167）

leetcode 167 两数之和2，输入有序数组

解题思路：双指针碰撞

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