https://leetcode.com/problems/two-sum-ii-input-array-is-sorted/description/
题目：在数组中找出2个数的和等于目标值。
思路：双指针，和大于目标值r–，小于目标值l++，否则 返回结果。
class Solution {
public:
vector<int> twoSum(
vector<int>& numbers,
int target) {
int l=
0,r=numbers.size()-
1;
vector<int>v;
while(l<r)
{
if(numbers[l]+numbers[r]==target)
{
v.push_back(l+
1);v.push_back(r+
1);
break;
}
else if(numbers[l]+numbers[r]>target) r--;
else l++;
}
return v;
}
};
