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:

(0)-->(1)
 |     |
 v     v
(2)-->(3)

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:

 --------.
/   (0)->(1)
|   / \  / \
|  v   v    v
->(4)<(3)<-(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.

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class Solution:
    def allPathsSourceTarget(self, graph: List[List[int]]) -> List[List[int]]:
        path = []
        n = len(graph)
        res = []
        def dfs(current: int) -> None:
            if current == n-1:
                res.append(path + [current])
                return
            path.append(current)
            for nxt in graph[current]:
                dfs(nxt)
            path.pop()
        dfs(0)
        return res