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2 seconds
256 megabytes
standard input
standard output
Permutation p is an ordered set of integers p1, p2, …, pn, consisting of n distinct positive integers, each of them doesn’t exceed n. We’ll denote the i-th element of permutation p as pi. We’ll call number n the size or the length of permutation p1, p2, …, pn.
You have a sequence of integers a1, a2, …, an. In one move, you are allowed to decrease or increase any number by one. Count the minimum number of moves, needed to build a permutation from this sequence.
The first line contains integer n (1 ≤ n ≤ 3·105) — the size of the sought permutation. The second line contains n integersa1, a2, …, an ( - 109 ≤ ai ≤ 109).
Print a single number — the minimum number of moves.
Please, do not use the %lld specifier to read or write 64-bit integers in С++. It is preferred to use the cin, cout streams or the %I64dspecifier.
2 3 0
2
3 -1 -1 2
6
In the first sample you should decrease the first number by one and then increase the second number by one. The resulting permutation is (2, 1).
In the second sample you need 6 moves to build permutation (1, 3, 2).
#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
using namespace std;
long long a[300005];
int main()
{
int n;
long long ans,tmp;
cin>>n;
for(int i=0;i<n;i++)cin>>a[i];
sort(a,a+n);
ans=0;
for(int i=0;i<n;i++)
{
tmp=(long long)(i+1)-a[i];
if(tmp<0)ans-=tmp;
else ans+=tmp;
}
cout<<ans<<endl;
return 0;
}