TwoSumSortedBestSolution.java

/*
 *
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.

*/

public class TwoSumSortedBestSolution {

    public int[] TwoSum(int[] numbers, int target) {
        
        if (numbers.length > 1){
            for(int i=0, j=numbers.length-1; i < j;){
                int sum = numbers[i]+numbers[j];
                if(sum == target){
                    return new int[]{i+1, j+1};
                }else if(sum > target){
                    j--;
                }else{
                    i++;
                }
            }
        }

        return null;
    }

    public static void main(String[] args) {
    
        int input[] = {-1, 0};
        TwoSumSortedBestSolution twoSumSortedBestSolution = new TwoSumSortedBestSolution();
        int[] result = twoSumSortedBestSolution.TwoSum(input, -1);
        if(result != null){
            for(int res: result){
                System.out.println(res);
            }
        }

    }
    
}