Find Vertices from Which Every Walk Terminates

### Problem In the directed graph, a terminal vertex has no outgoing edges. A vertex is safe when every path starting there eventually terminates instead of remaining in a cycle. Return every safe vertex label in increasing order. Self-loops are allowed. ```cpp class Solution { public: vector<int> eventualSafeNodes(vector<vector<int>>& graph); }; ``` ### Examples **Example 1:** ```text graph = [[1],[2],[],[3]] Output: [0,1,2] Explanation: The first chain terminates at2; vertex3 has a self-loop. ``` **Example 2:** ```text graph = [[1],[0],[]] Output: [2] Explanation: Vertices0 and1 form a cycle, while2 is terminal. ``` ### Constraints - Vertex count is 1 through 10000, with labels 0 through V-1. - Each neighbor list has 0 through V entries in strictly increasing order. - All labels are valid; self-loops may occur. - Total directed edge count is 1 through 40000. ### Contract considerations Return all safe labels in ascending order. ```hint Read the boundary condition When have all of a vertex's possible next steps been proved safe? ``` ### Boundary reminders Return all safe labels in ascending order.