167_TwoSum.cpp

// 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. 
//Please note that your returned answers (both index1 and index2) are not zero-based.

//You may assume that each input would have exactly one solution.

//Input: numbers={2, 7, 11, 15}, target=9
//Output: index1=1, index2=2


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

        return sum;
    }
};