CSES - Aalto Competitive Programming 2024 - wk11 - Homework - Results
Submission details
Task:Finding inverse
Sender:esya_rae
Submission time:2024-11-18 12:08:01 +0200
Language:Python3 (PyPy3)
Status:READY
Result:
Test results
testverdicttime
#1ACCEPTED0.04 sdetails
#2ACCEPTED0.04 sdetails
#3ACCEPTED0.04 sdetails
#4ACCEPTED0.04 sdetails
#5ACCEPTED0.04 sdetails
#6ACCEPTED0.05 sdetails
#7ACCEPTED0.04 sdetails
#8ACCEPTED0.05 sdetails
#9--details
#10--details
#11--details
#12--details
#13--details
#14--details

Code

import sys

sys.setrecursionlimit(10**6)
input = sys.stdin.readline



def sieve_primes(n):
    primes = []
    for i in range(2, n // 2 + 1):
        is_prime = True
        for j in primes:
            if i % j == 0:
                is_prime = False
        if is_prime:
            primes.append(i)
    return primes



def euler(n, primes):
    div = []
    for p in primes:
        if n % p == 0:
            div.append(p)
    # print(div)
    if not div:
        return n - 1
    c = n
    for d in div:
        c *= (d - 1)
        c //= d
    return c


def fast_exp(a, b, mod):
    if b == 0:
        return 1
    g = 1
    while b > 1:
        if b % 2 == 1:
            g = (g * a) % mod
            b -= 1
        a = (a * a) % mod
        b //= 2
    return (a * g) % mod

a, M = map(int, input().split())
e = euler(M, sieve_primes(M))
# print(e)
r = fast_exp(a, e - 1, M)
if (r * a) % M == 1:
    print(r)
else:
    print(-1)

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:

input
184120 505187

correct output
438779

user output
(empty)

Test 10

Verdict:

input
264601 885661

correct output
360221

user output
(empty)

Test 11

Verdict:

input
40310 590135

correct output
-1

user output
(empty)

Test 12

Verdict:

input
202254499 577081420

correct output
128866679

user output
(empty)

Test 13

Verdict:

input
539836073 888851205

correct output
797044652

user output
(empty)

Test 14

Verdict:

input
697847215 756971670

correct output
-1

user output
(empty)