797. All Paths From Source to Target ⭐
Medium
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.length2 <= n <= 150 <= graph[i][j] < ngraph[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.
func allPathsSourceTarget(graph [][]int) [][]int {
// DAG 有相無環，所以可以不用記走過哪些點
res := make([][]int, 0)
var helper func(int, []int)
helper = func(cur int, path []int) {
path = append(path, cur)
if cur == len(graph) - 1 {
temp := make([]int, len(path));
copy(temp, path)
res = append(res, temp)
} else {
for _, n := range graph[cur] {
helper(n, path)
}
}
}
helper(0, []int{})
return res
}