forked from mbobesic/algorithms-playground
-
Notifications
You must be signed in to change notification settings - Fork 0
/
PrimePath.py
77 lines (58 loc) · 1.72 KB
/
PrimePath.py
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
# link: https://open.kattis.com/problems/primepath
# name: Prime Path
__author__ = 'mislav'
from collections import deque
MAX_VALUE = 10000
digits = ['0', '1', '2', '3', '4', '5', '6', '7', '8', '9']
def get_transforms(number):
result = []
ns = str(number)
for x in xrange(4):
current = list(ns)
for y in digits:
current[x] = y
num = int("".join(current))
if num < 1000:
continue
if num == number:
continue
result.append(num)
return result
if __name__ == "__main__":
primes = [0]*(MAX_VALUE+2)
prev = [0]*(MAX_VALUE+2)
next = [0]*(MAX_VALUE+2)
for x in xrange(2, MAX_VALUE):
prev[x] = x - 1
next[x] = x + 1
i = 2
while i * i <= MAX_VALUE:
j = prev[MAX_VALUE // i + 1]
while j >= i:
primes[j * i] = i
next[prev[j * i]] = next[j * i]
prev[next[j * i]] = prev[j * i]
j = prev[j]
i = next[i]
n = int(raw_input())
while n > 0:
n -= 1
in_string = raw_input().split()
start = int(in_string[0])
end = int(in_string[1])
q = deque([(start, 0)])
visited = [False] * MAX_VALUE
result = 0
while len(q) > 0:
current = q.popleft()
if current[0] == end:
result = current[1]
break
for transform in get_transforms(current[0]):
if visited[transform]:
continue
visited[transform] = True
if primes[transform] != 0:
continue
q.append((transform, current[1]+1))
print result