Help me out in this problem

#1


leetcode
question link

#2

@aman212yadav are u there?

#3

yeah , what issue u r facing?

#4 

class Solution {
public:
    int findDuplicate(vector<int>& ar)
    {
       map<int,int> mp;
        int n=ar.size();
        for(int i=0;i<n;i++)
        {
            mp[ar[i]]=0;
        }
        for(int i=0;i<n;i++)
        {
            if(mp[ar[i]]==0)
            {
                mp[ar[i]]=1;
             }
             else
             {
                return ar[i];
            }
         }
        return -1; // it will never run,just to surpass warning i m adding this
    
        
    }
};
#5

i am getting error but i did able to debug it?

#6

@why is it so can you tell me

#7

without return statement compiler will think that function return type is int but we r not returning anything , hence it will raise error.

#8

@aman212yadav ee in question it is given it always contain duplictes then else part will definitely run in each case

#9

@shivammishra20121999

that we know na , compiler dont know about this