797. All Paths From Source to Target
Given a directed acyclic graph (DAG) of n
nodes labeled from 0
to n - 1
, find all possible paths from node 0
to node n - 1
and return them in any order.
The graph is given as follows: graph[i]
is a list of all nodes you can visit from node i
(i.e., there is a directed edge from node i
to node graph[i][j]
).
Example 1:
Input: graph = [[1,2],[3],[3],[]]
Output: [[0,1,3],[0,2,3]]
Explanation: There are two paths: 0 -> 1 -> 3 and 0 -> 2 -> 3.
Example 2:
Input: graph = [[4,3,1],[3,2,4],[3],[4],[]]
Output: [[0,4],[0,3,4],[0,1,3,4],[0,1,2,3,4],[0,1,4]]
Constraints:
n == graph.length
2 <= n <= 15
0 <= graph[i][j] < n
graph[i][j] != i
(i.e., there will be no self-loops).- All the elements of
graph[i]
are unique. - The input graph is guaranteed to be a DAG.
class Solution:
def allPathsSourceTarget(self, graph: List[List[int]]) -> List[List[int]]:
tempDict = collections.defaultdict(list)
for idx, edge in enumerate(graph):
if len(edge) == 0:
tempDict[idx].append(-1)
for vertex in edge:
tempDict[idx].append(vertex)
target = len(graph) - 1
res = []
def dfs(curNode, path):
if curNode == target:
res.append(path[:])
return
for i in tempDict[curNode]:
path.append(i)
dfs(i, path)
path.pop()
dfs(0,[0])
return res