Given an array of integers that is already sorted in ascending order, find two numbers such that they add up to a specific target number.
The function twoSum should return indices of the two numbers such that they add up to the target, where index1 must be less than index2.
Note:
- Your returned answers (both index1 and index2) are not zero-based.
- You may assume that each input would have exactly one solution and you may not use the same element twice.
Example:
Input: numbers = [2,7,11,15], target = 9 Output: [1,2] Explanation: The sum of 2 and 7 is 9. Therefore index1 = 1, index2 = 2.
用two pointer
时间：O(N), 空间：O(1)
class Solution { public int[] twoSum(int[] numbers, int target) { int l = 0, r = numbers.length - 1; while(l < r) { if(numbers[l] + numbers[r] > target) r--; else if(numbers[l] + numbers[r] < target) l++; else break; } return new int[] {l + 1, r + 1}; } }