167. Two Sum II - Input array is sorted

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 1:

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.

Example 2:

Input: numbers = [2,3,4], target = 6
Output: [1,3]

Example 3:

Input: numbers = [-1,0], target = -1
Output: [1,2]

Constraints:

• 2 <= nums.length <= 3 * 104
• -1000 <= nums[i] <= 1000
• nums is sorted in increasing order.
• -1000 <= target <= 1000

# @lc code=start
using LeetCode

# using double pointers
function two_sum_167(numbers::Vector{Int}, target::Int)::Vector{Int}
    left, right = 1, length(numbers)
    while left < right
        num = numbers[left] + numbers[right]
        if num > target
            right -= 1
        elseif num < target
            left += 1
        else
            return [left, right]
        end
    end
    [-1, -1]
end

# @lc code=end

two_sum_167 (generic function with 1 method)

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