There are N
network nodes, labelled 1
to N
.
Given times
, a list of travel times as directed edges times[i] =
(u, v, w)
, where u
is the source node, v
is the target
node, and w
is the time it takes for a signal to travel from source to target.
Now, we send a signal from a certain node K
. How long will it take for all nodes
to receive the signal? If it is impossible, return -1
.
Example 1:
Input: times = [[2,1,1],[2,3,1],[3,4,1]], N = 4, K = 2 Output: 2
Note:
N
will be in the range [1, 100]
.K
will be in the range [1, N]
.times
will be in the range [1, 6000]
.times[i] = (u, v, w)
will have 1 <= u, v <= N
and 0 <= w <= 100
.