Use sieve method instead of algebraic method
This commit is contained in:
parent
272523b8b2
commit
259f974f32
70
13/part2
70
13/part2
|
@ -1,50 +1,32 @@
|
|||
#!/usr/bin/python3
|
||||
import time
|
||||
|
||||
def ext_euclid(a, b):
|
||||
"""
|
||||
returns solutions x and y for equation ax + by = gcd(a, b)
|
||||
"""
|
||||
def shuttle_generator():
|
||||
with open("input") as fh:
|
||||
now = int(fh.readline())
|
||||
for i, x in enumerate(fh.readline().split(",")):
|
||||
if x != "x":
|
||||
x = int(x)
|
||||
yield i, x
|
||||
|
||||
(old_r, r) = (a, b)
|
||||
(old_s, s) = (1, 0)
|
||||
(old_t, t) = (0, 1)
|
||||
shuttle = shuttle_generator()
|
||||
|
||||
while r:
|
||||
quotient = old_r // r
|
||||
(old_r, r) = (r, old_r - quotient * r)
|
||||
(old_s, s) = (s, old_s - quotient * s)
|
||||
(old_t, t) = (t, old_t - quotient * t)
|
||||
return old_s, old_t, old_r
|
||||
def check(t, tests):
|
||||
for i, n in tests:
|
||||
if (t + i) % n != 0:
|
||||
return False
|
||||
return True
|
||||
|
||||
n = []
|
||||
a = []
|
||||
with open("input") as fh:
|
||||
now = int(fh.readline())
|
||||
for i, x in enumerate(fh.readline().split(",")):
|
||||
if x != "x":
|
||||
x = int(x)
|
||||
n.append(x)
|
||||
a.append((x - i) % x)
|
||||
t = 0
|
||||
step = 1
|
||||
n = 1
|
||||
tests = []
|
||||
while True:
|
||||
if check(t, tests):
|
||||
print(t, "matches", tests)
|
||||
time.sleep(2)
|
||||
step *= n
|
||||
i, n = next(shuttle)
|
||||
tests.append((i, n))
|
||||
t += step
|
||||
|
||||
print(n)
|
||||
print(a)
|
||||
|
||||
n1 = n.pop()
|
||||
n2 = n.pop()
|
||||
a1 = a.pop()
|
||||
a2 = a.pop()
|
||||
m1, m2, _ = ext_euclid(n1, n2)
|
||||
assert _ == 1
|
||||
x = a1 * m2 * n2 + a2 * m1 * n1
|
||||
print(x)
|
||||
while n:
|
||||
n1 = n1 * n2
|
||||
a1 = x
|
||||
|
||||
n2 = n.pop()
|
||||
a2 = a.pop()
|
||||
|
||||
m1, m2, _ = ext_euclid(n1, n2)
|
||||
assert _ == 1
|
||||
x = a1 * m2 * n2 + a2 * m1 * n1
|
||||
print(x)
|
||||
|
|
Loading…
Reference in New Issue