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]]
Example 3:
Input: graph = [[1],[]] Output: [[0,1]]
Example 4:
Input: graph = [[1,2,3],[2],[3],[]] Output: [[0,1,2,3],[0,2,3],[0,3]]
Example 5:
Input: graph = [[1,3],[2],[3],[]] Output: [[0,1,2,3],[0,3]]
Constraints:
n == graph.length
2 <= n <= 15
0 <= graph[i][j] < n
graph[i][j] != i
(i.e., there will be no self-loops).- The input graph is guaranteed to be a DAG.
Rust Solution
struct Solution;
impl Solution {
fn all_paths_source_target(graph: Vec<Vec<i32>>) -> Vec<Vec<i32>> {
let mut res = vec![];
let mut path: Vec<i32> = vec![];
let n = graph.len();
Self::dfs(0, &mut path, &mut res, &graph, n);
res
}
fn dfs(u: i32, path: &mut Vec<i32>, paths: &mut Vec<Vec<i32>>, graph: &[Vec<i32>], n: usize) {
path.push(u);
if u as usize == n - 1 {
paths.push(path.clone());
} else {
for &v in &graph[u as usize] {
Self::dfs(v, path, paths, graph, n);
}
}
path.pop();
}
}
#[test]
fn test() {
let graph = vec_vec_i32![[1, 2], [3], [3], []];
let res = vec_vec_i32![[0, 1, 3], [0, 2, 3]];
assert_eq!(Solution::all_paths_source_target(graph), res);
}
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