-
Notifications
You must be signed in to change notification settings - Fork 17
/
jump-game-iv.py
43 lines (31 loc) · 1.36 KB
/
jump-game-iv.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
from typing import List, Dict, Iterator, Set, Deque, Tuple
from functools import lru_cache
from collections import deque
class Solution:
def minJumps(self, array: List[int]) -> int:
def gen_value_pos_map() -> Dict[int, List[int]]:
value_pos_map: Dict[int, List[int]] = {}
for pos, value in enumerate(array):
value_pos_map.setdefault(value, [])
value_pos_map[value].append(pos)
for key in value_pos_map.keys():
value_pos_map[key].reverse()
return value_pos_map
value_pos_map = gen_value_pos_map()
def neighbors(pos: int) -> Iterator[int]:
for neigh_pos in (value_pos_map[array[pos]] + [pos - 1, pos + 1]):
if 0 <= neigh_pos < len(array) and neigh_pos != pos:
yield neigh_pos
queue: Deque[Tuple[int, int]] = deque()
min_jumps = [len(array)] * len(array)
min_jumps[0] = 0
queue.append((0, 0))
while queue:
jumps, pos = queue.popleft()
for neigh_pos in neighbors(pos):
if neigh_pos == len(array) - 1:
return jumps + 1
if min_jumps[neigh_pos] > jumps + 1:
min_jumps[neigh_pos] = jumps + 1
queue.append((jumps + 1, neigh_pos))
return min_jumps[-1]