cpp-flashcards/org/study_deck_02/dsa/graphs/0802-find-eventual-safe-states.org

#+ANKI_DECK: study_deck_02
* TODO 0802. Find Eventual Safe States :medium:
:PROPERTIES:
:NEETCODE: [[file:../../roadmap.org::*0802. Find Eventual Safe States][0802. Find Eventual Safe States]]
:END:

There is a directed graph of ~n~ nodes with each node labeled from ~0~ to ~n - 1~. The graph is represented by a *0-indexed* 2D integer array ~graph~ where ~graph[i]~ is an integer array of nodes adjacent to node ~i~, meaning there is an edge from node ~i~ to each node in ~graph[i]~.

A node is a *terminal node* if there are no outgoing edges. A node is a *safe node* if every possible path starting from that node leads to a *terminal node* (or another safe node).

Return /an array containing all the *safe nodes* of the graph/. The answer should be sorted in *ascending* order.

*Example 1:*


#+begin_src
Input: graph = [[1,2],[2,3],[5],[0],[5],[],[]]
Output: [2,4,5,6]
Explanation: The given graph is shown above.
Nodes 5 and 6 are terminal nodes as there are no outgoing edges from either of them.
Every path starting at nodes 2, 4, 5, and 6 all lead to either node 5 or 6.
#+end_src


*Example 2:*


#+begin_src
Input: graph = [[1,2,3,4],[1,2],[3,4],[0,4],[]]
Output: [4]
Explanation:
Only node 4 is a terminal node, and every path starting at node 4 leads to node 4.
#+end_src


*Constraints:*

 - ~n == graph.length~

 - ~1 <= n <= 10^{4}~

 - ~0 <= graph[i].length <= n~

 - ~0 <= graph[i][j] <= n - 1~

 - ~graph[i]~ is sorted in a strictly increasing order.

 - The graph may contain self-loops.

 - The number of edges in the graph will be in the range ~[1, 4 * 10^{4}]~.

** TODO Approach
Write your approach here.

** TODO Python
#+begin_src python
class Solution:
    def eventualSafeNodes(self, graph: List[List[int]]) -> List[int]:
#+end_src

** TODO C++
#+begin_src cpp
class Solution {
public:
    vector<int> eventualSafeNodes(vector<vector<int>>& graph) {
        
    }
};
#+end_src