Codeforces 495B – Modular Equations

This is a very interesting divisor count problem.


/*
User ID: Tanmoy_Datta
Link : http://codeforces.com/problemset/problem/495/B
*/

#include <bits/stdc++.h>

#define pii pair <int,int>
#define sc scanf
#define pf printf
#define Pi 2*acos(0.0)
#define ms(a,b) memset(a, b, sizeof(a))
#define pb(a) push_back(a)
#define MP make_pair
#define oo 1<<29
#define dd double
#define ll long long
#define EPS 10E-10
#define ff first
#define ss second
#define MAX 10000
#define SZ(a) (int)a.size()
#define getint(a) scanf("%d",&a)
#define loop(i,n) for(int i=0;i<n;i++)
#define all(a) a.begin(),a.end()
#define intlim 2147483648
#define inf 1000000
#define rtintlim 46340
#define llim 9223372036854775808
#define rtllim 3037000499
#define ull unsigned long long
#define I int

using namespace std;

/* Bits operation */
int Set(int n,int pos)  { return n = n | 1<<pos;}
bool check(int n,int pos) { return n & 1<<pos;}
int Reset(int n, int pos) { return n=n & ~(1<<pos);}

int main()
{
    ///freopen("in.txt","r",stdin);
    ///freopen("out.txt","w",stdout);
    ll a,b;
    cin>>a>>b;
    if(a==b)
        cout<<"infinity"<<endl;
    else
    {
        a-=b;
        int ans=0;
        for(int i=1;i*i<=a;i++)
        {
            if(a%i==0)
            {
                if(i>b)
                    ans++;
                if(a/i!=i && (a/i)>b)
                    ans++;
            }
        }
        cout<<ans<<endl;
    }
    return 0;
}

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