Cod sursa(job #2663032)

Utilizator YusyBossFares Yusuf YusyBoss Data 25 octombrie 2020 10:16:21
Problema Suma divizorilor Scor 10
Compilator cpp-64 Status done
Runda Arhiva de probleme Marime 1.53 kb
#include <iostream>
#include <stdio.h>
#define MOD 9901

using namespace std;

int prod;

void rid_put(int x, int put, int mod) {
  if (put == 0)
    return;
  if (put % 2 == 1)
    prod = (1ll * prod * x) % mod;
  x = (1ll * x * x) % mod;
  rid_put(x, put / 2, mod);
}

int phi(int x) {
  int d, sol;

  sol = x;
  for (d = 2; d * d <= x; d++)
    if (x % d == 0) {
      while (x % d == 0)
        x /= d;
      sol = sol / d * (d - 1);
    }

  if (x > 1)
    sol = sol / x * (x - 1);
  return sol;
}

int inv_mod(int a, int n) {
  int nr = phi(n);
  prod = 1;
  rid_put(a, nr - 1, n);
  return prod;
}

int sum_div(int a, int b) {
  int d, put, nr1, nr2, sol;
  sol = 1;
  for (d = 2; d * d <= a; d++) {
    put = 0;
    while (a % d == 0) {
      put++;
      a /= d;
    }
    if (put > 0) {
      put *= b;
      prod = 1;
      rid_put(d % MOD, put + 1, MOD);
      nr1 = (prod - 1) % MOD;
      nr2 = inv_mod((d - 1) % MOD, MOD);
      sol = (1ll * sol * nr1) % MOD;
      sol = (1ll * sol * nr2) % MOD;
    }
  }
  if (a > 0) {
    put = b;
    prod = 1;
    rid_put(d, put + 1, MOD);
    nr1 = (prod - 1) % MOD;
    nr2 = inv_mod(d - 1, MOD);
    sol = (1ll * sol * nr1) % MOD;
    sol = (1ll * sol * nr2) % MOD;
  }
  return sol;
}

int main() {
  FILE *fin, *fout;
  int a, b;

  fin = fopen("sumdiv.in", "r");
  fscanf(fin, "%d%d", &a, &b);
  fclose( fin );

  fout = fopen("sumdiv.out", "w");
  fprintf(fout, "%d", sum_div(a, b));
  fclose( fout );
  return 0;
}