Last updated on October 25th, 2024 at 10:26 pm

Here, We see Two Sum II – Input Array Is Sorted LeetCode Solution. This Leetcode problem is done in many programming languages like C++, Java, JavaScript, Python, etc. with different approaches.

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Two Sum II – Input Array Is Sorted LeetCode Solution

Problem Statement

Given a 1-indexed array of integers numbers that is already sorted in non-decreasing order, find two numbers such that they add up to a specific target number. Let these two numbers be numbers[index1] and numbers[index2] where 1 <= index1 < index2 <= numbers.length.

Return the indices of the two numbers, index1 and index2, added by one as an integer array [index1, index2] of length 2.

The tests are generated such that there is exactly one solution. You may not use the same element twice.

Your solution must use only constant extra space.

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. We return [1, 2].

Example 2:

Input: numbers = [2,3,4], target = 6
Output: [1,3]
Explanation: The sum of 2 and 4 is 6. Therefore index1 = 1, index2 = 3. We return [1, 3].

Example 3:

Input: numbers = [-1,0], target = -1
Output: [1,2]
Explanation: The sum of -1 and 0 is -1. Therefore index1 = 1, index2 = 2. We return [1, 2].

1. Two Sum II – Input Array Is Sorted Leetcode Solution C++

class Solution {
public:
    vector<int> twoSum(vector<int>& numbers, int target) {
    int l = 0;
    int r = numbers.size() - 1;

    while (numbers[l] + numbers[r] != target)
      if (numbers[l] + numbers[r] < target)
        ++l;
      else
        --r;

    return {l + 1, r + 1};
  }        
};

2. Two Sum II – Input Array Is Sorted Leetcode Solution Java

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

    while (numbers[l] + numbers[r] != target)
      if (numbers[l] + numbers[r] < target)
        ++l;
      else
        --r;

    return new int[] {l + 1, r + 1};        
    }
}

3. Two Sum II – Input Array Is Sorted Leetcode Solution JavaScript

var twoSum = function(numbers, target) {
    let p1=0, p2=numbers.length;
    while(p1<p2){
        if(numbers[p1]+numbers[p2]==target) return [p1+1,p2+1];
        else if(numbers[p1]+numbers[p2]<target) p1++;
        else p2--;
    }    
};

4. Two Sum II – Input Array Is Sorted Leetcode Solution Python

class Solution(object):
    def twoSum(self, numbers, target):
        l = 0
        r = len(numbers) - 1

        while l < r:
            summ = numbers[l] + numbers[r]
            if summ == target:
                return [l + 1, r + 1]
            if summ < target:
                l += 1
            else:
                r -= 1