0797.All Paths From Source to Target

797. All Paths From Source to Target

Given a directed, acyclic graph of N nodes. Find all possible paths from node 0 to node N-1, and return them in any order.

The graph is given as follows: the nodes are 0, 1, …, graph.length - 1. graph[i] is a list of all nodes j for which the edge (i, j) exists.

Example: Input: [[1,2], [3], [3], []] Output: [[0,1,3],[0,2,3]] Explanation: The graph looks like this: 0—>1 | | v v 2—>3 There are two paths: 0 -> 1 -> 3 and 0 -> 2 -> 3. Note:

The number of nodes in the graph will be in the range [2, 15]. You can print different paths in any order, but you should keep the order of nodes inside one path.

思路

这题直接DFS,递归遍历就好了

时间复杂度 O(N)
空间复杂度 O(N)

代码

pub fn all_paths_source_target(graph: Vec<Vec>) -> Vec<Vec> {

let mut paths = Vec::with_capacity(graph.len()); let mut path = Vec::with_capacity(graph.len());

path.push(0);

find_N(0,&mut path,&mut paths,&graph);

return paths; }

pub fn find_N(poient:i32,mut path:&mut Vec,mut paths:&mut Vec<Vec>,graph:&Vec<Vec>){ if poient == (graph.len()-1) as i32 { paths.push(path.clone()); } else { for next in &graph[poient as usize]{ path.push(*next); find_N(*next,&mut path,&mut paths,& graph); path.pop(); } } }

执行用时: 12 ms
内存消耗: 2.4 MB

题型与相似题

题型

1.DFS 2.graph

相似题

代码链接

all_paths_from_source_to_target