1. Description
2. Solution
**解析:**Version 1,使用广度优先搜索,其实是个二叉树遍历问题,使用字典记录搜索过的索引,每次根据当前值计算下一次搜索的左右索引,如果在数组范围内且没被搜索过,则将其记录到队列中,依次搜索,如果当前值为0
,返回True
,如果队列为空时都没找到,则返回False
。
- Version 1
class Solution:
def canReach(self, arr: List[int], start: int) -> bool:
n = len(arr)
queue = collections.deque()
queue.append(start)
records = {}
while queue:
index = queue.popleft()
value = arr[index]
if value == 0:
return True
records[index] = value
left = index - value
right = index value
if left > -1 and left not in records:
queue.append(left)
if right < n and right not in records:
queue.append(right)
return False
Reference
- https://leetcode.com/problems/jump-game-iii/