[LeetCode]Two Sum II - Input array is sorted

因为input是sorted的，所以我们用双指针即可解决这道题。时间复杂度O(N)，常数空间，代码如下：

	class Solution {
	public:
	vector<int> twoSum(vector<int>& numbers, int target) {
	int len = numbers.size(), i = 0, j = len - 1;
	while(i < j)
	{
	int sum = numbers[i] + numbers[j];
	if(sum < target)++i;
	else if(sum > target)--j;
	else return {i + 1, j + 1};
	}
	return {-1, -1};
	}
	};

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