Cod sursa(job #1477368)

Utilizator eu3neuomManghiuc Teodor-Florin eu3neuom Data 26 august 2015 01:57:20
Problema Suma divizorilor Scor 100
Compilator cpp Status done
Runda Arhiva de probleme Marime 1.84 kb
#include <iostream>
#include <fstream>

using namespace std;

ifstream fin("sumdiv.in");
ofstream fout("sumdiv.out");

const int MOD = 9901;

int a, b, p, nr;

int lg_power(int x){
    if(x == 0) return 1;
    int v = lg_power(x / 2);
    v = (1LL * v * v) % MOD;
    if(x % 2) v = (1LL * v * p) % MOD;
    return v;
}

int gcd(int a, int b, int &x, int &y){
    if(b == 0){
        x = 1;
        y = 0;
        return a;
    }
    int d, xp, yp;
    d = gcd(b, a % b, xp, yp);
    x = yp;
    y = xp - yp * (a / b);
    return d;
}

int solve(){
    int k = 0, x, inv, y, ans = 1, z;
    while(a % 2 == 0){
        a /= 2;
        k++;
    }
    if(k > 0){
        p = 2;
        x = lg_power(k * b + 1) - 1;
        if(x <= 0) x += MOD;
        y = gcd(1, MOD, inv, y);
        if(inv <= 0) inv += MOD;
        ans = 1LL * ans * x * inv % MOD;
    }
    for(int i = 3; i * i <= nr; i += 2){
        if(a % i == 0){
            k = 0;
            while(a % i == 0){
                a /= i;
                k++;
            }
            p = i;
            x = lg_power(k * b + 1) - 1;
            if(x <= 0) x += MOD;
            y = gcd((i - 1) % MOD, MOD, inv, y);
            if(inv <= 0) inv += MOD;
            ans = 1LL * ans * x * inv % MOD;
        }
    }
    if(a != 1){
        p = a;
        x = lg_power(b + 1) - 1;
        if(x <= 0) x += MOD;
        y = gcd((a - 1) % MOD, MOD, inv, y);
        if(inv <= 0) inv += MOD;
        if(x != MOD || inv != MOD){
            ans = (1LL * ans * x * inv) % MOD;
        } else {
            ans = (1LL * ans * (b + 1)) % MOD;
        }
    }
    return ans;
}

int main(){
    int x, inv, y;
    fin >> a >> b;
    nr = a;
    if(a == 0 || b == 0 || a == 1){
        fout << 1;
    } else {
        fout << solve();
    }
    return 0;
}