Two Sum.cpp

#include <algorithm>

class Solution {
public:

class Pair
{
    public: 
    int index; 
    int val;  
    Pair(int i, int v)
    {
        index=i; 
        val=v;
    }
};

class less_than_key
{
    public: 
    const bool operator() (const Pair & a, const Pair& b)
    {
        return (a.val < b.val);
    }
};

    vector<int> twoSum(vector<int> &numbers, int target) {
        // Start typing your C/C++ solution below
        // DO NOT write int main() function
     
    vector<int> result; 
    int length=numbers.size(); 
    vector<Pair> pairs; 
    for(int i=0; i<length; i++)
    {
        pairs.push_back(Pair(i+1, numbers[i]));
    }
    sort(pairs.begin(), pairs.end(), less_than_key());
    int start=0, end=length-1; 
    while(start<end)
    {
        int temp=pairs[start].val + pairs[end].val; 
        if(temp==target) 
        {
            result.push_back(pairs[start].index);
            result.push_back(pairs[end].index);
            break;
        }
        if(temp<target) start++; 
        if(temp>target) end--; 
    }
    sort(result.begin(), result.end());
    return result; 
    }
};

Two Sum.java

public class Solution {
    class Pair
    {
        int index; 
        int val; 
        Pair(int i, int v)
        {
            index=i; 
            val=v;
        }
    }
    public int[] twoSum(int[] numbers, int target) {
        // Start typing your Java solution below
        // DO NOT write main() function
        Pair pairs[]=new Pair[numbers.length];
        int result[]=new int[2];
        for(int i=0; i<numbers.length; i++)
        {
            pairs[i]=new Pair(i+1, numbers[i]);
        }
        Arrays.sort(pairs, PARI_ORDER);
        int start=0, end=numbers.length-1; 
        while(start<end)
        {
            int temp=pairs[start].val+pairs[end].val; 
            if(temp==target)
            {
                result[0]=pairs[start].index;
                result[1]=pairs[end].index;
                break; 
            }
            if(temp>target) end--; 
            if(temp<target) start++;
        }
        Arrays.sort(result);
        return result; 
    }
    
   public static final Comparator<Pair> PARI_ORDER=new Comparator<Pair>()
    {
	public int compare(Pair i, Pair j)
	{
        return new Integer(i.val).compareTo(new Integer(j.val));   
        }
	};    
}