Check two array are equal or not in O(n):🙄

#include<bits/stdc++.h>
using namespace std;
int main()
{
   int a[]={1,2,5,4,0};
   int b[]={2,4,5,0,1};
   int n=5;
   //find that both array are equal in O(n)
   map<int,int>mp1;
   map<int,int>mp2;
   for(int i=0;i<n;i++)
   {
       mp1[a[i]]++;
       mp2[b[i]]++;
   }
   if(mp1==mp2)
   cout<<"both same";
   else
   cout<<"different";
    return 0;
}