587A - Duff and Weight Lifting - CodeForces Solution

#include <bits/stdc++.h>
int  a[1001000],n,i,b,sum=0;
using namespace std;
int main()
{
cin>>n;
for(i=0;i<n;i++)
{
scanf("%d",&b);
a[b]++;
}
for(i=0;i<=1001000;i++)
{
sum+=a[i]%2;
a[i+1]+=a[i]/2;
}
cout<<sum;
}