Array Pair Sum Divisibility Problem

//{ Driver Code Starts

#include <bits/stdc++.h>

using namespace std;

 

// } Driver Code Ends

class Solution {

  public:

    bool canPair(vector<int> nums, int k) {

        // Code here.

        map<int,int>m;

       if((nums.size())&1)

       {

           return false;

       }

       else

       {

           for(int i=0;i<nums.size();i++)

           {

               m[nums[i]%k]++;

           }

           auto it=m.begin();

           for(int i=0;i<m.size();i++)

           {

               if(it->first==0 )

               {

                   if((it->second)%2!=0){

                   return false;

                   }

               }

               else if(2*(it->first)==k )

               {

                   if((it->second)%2!=0){

                   return false;

                   }

               }

               else if(m[i]!=m[k-i])

               {

                   return false;

               }

               it++;

           }

           

           return true;

       }

    }

};