CSES - Aalto Competitive Programming 2024 - wk11 - Homework - Results
Submission details
Task:Finding inverse
Sender:fabiank
Submission time:2024-11-14 19:20:37 +0200
Language:C++ (C++17)
Status:READY
Result:ACCEPTED
Test results
testverdicttime
#1ACCEPTED0.00 sdetails
#2ACCEPTED0.00 sdetails
#3ACCEPTED0.00 sdetails
#4ACCEPTED0.00 sdetails
#5ACCEPTED0.00 sdetails
#6ACCEPTED0.00 sdetails
#7ACCEPTED0.00 sdetails
#8ACCEPTED0.00 sdetails
#9ACCEPTED0.00 sdetails
#10ACCEPTED0.00 sdetails
#11ACCEPTED0.00 sdetails
#12ACCEPTED0.00 sdetails
#13ACCEPTED0.00 sdetails
#14ACCEPTED0.00 sdetails

Code

#include <bits/stdc++.h>
#define REP(i, a, b) for (int i = a; i < b; i++)
// Type Aliases for 1D and 2D vectors with initialization
#define vll(n, val) vector<long long>(n, val) // 1D vector of long longs with size n, initialized to val
#define ll long long
#define vvi(n, m, val) vector<vector<int>>(n, vector<int>(m, val)) // 2D vector of ints (n x m), initialized to val
#define vvll(n, m, val) vector<vector<long long>>(n, vector<long long>(m, val)) // 2D vector of long longs (n x m), initialized to val
using namespace std;
void print_vector(vector<int> &x)
{
for (int v : x)
{
cout << v << " ";
}
cout << "\n";
}
void print_matrix(vector<vector<int>> &matrix)
{
cout << "\n"
<< "----------------" << "\n";
for (vector<int> row : matrix)
{
print_vector(row);
}
cout << "\n"
<< "----------------" << "\n";
}
int modpow(int x, int n, int m)
{
if (n == 0)
return 1 % m;
long long u = modpow(x, n / 2, m);
u = (u * u) % m;
if (n % 2 == 1)
u = (u * x) % m;
return u;
}
vector<int> factors(int n)
{
vector<int> f;
for (int x = 2; x * x <= n; x++)
{
while (n % x == 0)
{
f.push_back(x);
n /= x;
}
}
if (n > 1)
f.push_back(n);
return f;
}
int euler_totient(int n)
{
vector<int> prime_factors = factors(n);
// print_vector(prime_factors);
int result = 1;
int last_factor = 2;
int last_factor_count = 0;
for (int factor : prime_factors)
{
if (factor == last_factor)
{
last_factor_count++;
}
else
{
result *= (last_factor - 1);
for (int i = 1; i < last_factor_count; i++)
{
result *= last_factor;
}
last_factor = factor;
last_factor_count = 1;
}
}
result *= (last_factor - 1);
for (int i = 1; i < last_factor_count; i++)
{
result *= last_factor;
}
return result;
}
int gcd(int a, int b)
{
if (b == 0)
{
return a;
}
return gcd(b, a % b);
}
int main()
{
int a, M;
cin >> a >> M;
if (gcd(a, M) != 1)
{
cout << -1 << endl;
return 0;
}
int euler_tot = euler_totient(M);
cout << modpow(a, euler_tot - 1, M) << endl;
}

Test details

Test 1

Verdict: ACCEPTED

input
6 7

correct output
6

user output
6

Test 2

Verdict: ACCEPTED

input
0 7

correct output
-1

user output
-1

Test 3

Verdict: ACCEPTED

input
5 78

correct output
47

user output
47

Test 4

Verdict: ACCEPTED

input
89 99

correct output
89

user output
89

Test 5

Verdict: ACCEPTED

input
0 61

correct output
-1

user output
-1

Test 6

Verdict: ACCEPTED

input
897 947

correct output
625

user output
625

Test 7

Verdict: ACCEPTED

input
419 538

correct output
217

user output
217

Test 8

Verdict: ACCEPTED

input
32 938

correct output
-1

user output
-1

Test 9

Verdict: ACCEPTED

input
184120 505187

correct output
438779

user output
438779

Test 10

Verdict: ACCEPTED

input
264601 885661

correct output
360221

user output
360221

Test 11

Verdict: ACCEPTED

input
40310 590135

correct output
-1

user output
-1

Test 12

Verdict: ACCEPTED

input
202254499 577081420

correct output
128866679

user output
128866679

Test 13

Verdict: ACCEPTED

input
539836073 888851205

correct output
797044652

user output
797044652

Test 14

Verdict: ACCEPTED

input
697847215 756971670

correct output
-1

user output
-1