Question

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.

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.

How to convert this Java code to C++ code?

Java

class Solution {
public int[] twoSum(int[] numbers, int target) {
int left = 0, right = numbers.length() - 1;

while(left < right) {

int sum = numbers[left] + numbers[right];

if(sum == target) return new int[] {left +1, right + 1};

else if(sum > target) --right;

else ++left;

}

  
}
}

C++

class Solution {
public:
vector<int> twoSum(vector<int>& numbers, int target) {
// vector<vector <int>> res; do we use a 2d vector?
int left = 0, right = numbers.size() - 1;
while(left < right) {
int sum = numbers[left] + numbers[right];
if(sum == target)
return //is it a 2d vector thing?
else if(sum > target)
--right;
else
++left;
}
return NULL;
}
};

Kindly let me know. Your help will be much appreciated.

Answer 1

#include <iostream>
#include <vector>
using namespace std;

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