CF 546B Soldier and Badges

#include <iostream>
#include <cstdio>
#include <cstring>
using namespace std;

bool pos[100000];
long long  data[3100];
int main()
{
int n;
while(~scanf("%d",&n))
{
long long  ans = 0;
memset(pos,0,sizeof(pos));
for(int i = 1;i <= n;i ++)
{
scanf("%d",&data[i]);
if(pos[data[i]] == 0)
pos[data[i]] = 1;
else if(pos[data[i]])
{
for(int j = data[i] + 1 ;;j ++)
{
if(pos[j] == 0)
{
ans += j-data[i];
pos[j] = 1;
break;
}
}

}
}
cout<<ans<<endl;
}
return 0;
}