Jump game iv
class Solution:
def minJumps(self, arr: List[int]) -> int:
n = len(arr)
if n <= 1:
return 0
g = collections.defaultdict(list)
for i in range(len(arr)):
g[arr[i]].append(i)
q = collections.deque([0])
visited = set()
steps = 0
while q:
size = len(q)
for i in range(size):
curr = q.popleft()
if curr == n - 1:
return steps
nextNodes = g[arr[curr]]
for j in range(len(nextNodes)):
if nextNodes[j] not in visited:
visited.add(nextNodes[j])
q.append(nextNodes[j])
nextNodes.clear()
for j in [curr - 1, curr + 1]:
if 0 <= j < len(arr) and j not in visited:
visited.add(j)
q.append(j)
steps += 1
return -1
Jump Game IV
Given an array of integers arr, you are initially positioned at the first index of the array.
In one step you can jump from index i to index:
i + 1where:i + 1 < arr.length.i - 1where:i - 1 >= 0.jwhere:arr[i] == arr[j]andi != j.
Return the minimum number of steps to reach the last index of the array.
Notice that you can not jump outside of the array at any time.
Example 1:
Input: arr = [100,-23,-23,404,100,23,23,23,3,404] Output: 3 Explanation: You need three jumps from index 0 --> 4 --> 3 --> 9. Note that index 9 is the last index of the array.
Example 2:
Input: arr = [7] Output: 0 Explanation: Start index is the last index. You do not need to jump.
Example 3:
Input: arr = [7,6,9,6,9,6,9,7] Output: 1 Explanation: You can jump directly from index 0 to index 7 which is last index of the array.
Constraints:
1 <= arr.length <= 5 * 104-108 <= arr[i] <= 108