Cave Painting
Hazrat Ali
Some numbers, carved in chaotic order, immediately attracted his attention. Imp rapidly proposed a guess that they are the remainders of division of a number n by all integers i from 1 to k. Unfortunately, there are too many integers to analyze for Imp.
Imp wants you to check whether all these remainders are distinct. Formally, he wants to check, if all 
, 1 ≤ i ≤ k, are distinct, i. e. there is no such pair (i, j) that:
- 1 ≤ i < j ≤ k,
, where 
is the remainder of division x by y.
The only line contains two integers n, k (1 ≤ n, k ≤ 1018).
Print "Yes", if all the remainders are distinct, and "No" otherwise.
You can print each letter in arbitrary case (lower or upper).
4 4
No
5 3
Yes
Solution
#include <bits/stdc++.h>
using namespace std;
int main()
{
long long n, k;
cin >> n >> k;
if (k == 1)
{
cout << "Yes" << endl;
}
else
{
set<long long> s;
long long ans = 0;
for (long long i = 1; i <= k; i++)
{
s.insert(n % i);
ans++;
if (ans != s.size())
{
break;
}
}
if (ans == s.size())
{
cout << "Yes" << endl;
}
else
{
cout << "No" << endl;
}
}
return 0;
}