167. Two Sum II - Input array is sorted

class Solution {
    public int[] twoSum(int[] numbers, int target) {
      //sanity check
      if(numbers == null || numbers.length <2 ){
        return null;
      }
      
      int[] result = new int[2];
      int i = 0;
      int j = numbers.length - 1;
      
      while( i < j){
        int sum = numbers[i] + numbers[j];
        if( sum == target){
          result[0] = i+ 1;
          result[1] = j+ 1;
          break;
          
        }else if( sum > target){
          j--;
        }else{
          i++;
        }
      } 
      return result;
    }
}

 

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.

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