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Diffstat (limited to 'eventual_safe_states.cpp')
-rw-r--r-- | eventual_safe_states.cpp | 57 |
1 files changed, 0 insertions, 57 deletions
diff --git a/eventual_safe_states.cpp b/eventual_safe_states.cpp deleted file mode 100644 index 659115b..0000000 --- a/eventual_safe_states.cpp +++ /dev/null @@ -1,57 +0,0 @@ -// 802. Find Eventual Safe States -#include "leetcode.h" - -/* - * 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. - */ - -class Solution { - unordered_set<int> cycle_nodes, safe_nodes; - bool dfs(const vvd(int) & graph, int i, unordered_set<int> visited) { - if (safe_nodes.find(i) != safe_nodes.end()) - return true; - if (cycle_nodes.find(i) != cycle_nodes.end()) - return false; - if (visited.find(i) != visited.end()) { - cycle_nodes.insert(i); - return false; - } - visited.insert(i); - for (int node : graph[i]) - if (!dfs(graph, node, visited)) { - cycle_nodes.insert(i); - return false; - } - safe_nodes.insert(i); - return true; - } - -public: - vector<int> eventualSafeNodes(vvd(int) & graph) { - vector<int> ans; - unordered_set<int> visited; - for (int i = 0; i < graph.size(); i++) - if (dfs(graph, i, visited)) - ans.push_back(i); - return ans; - } -}; - -int main() { - Solution obj; - vvd(int) g1 = {{1, 2}, {2, 3}, {5}, {0}, {5}, {}, {}}; - vvd(int) g2 = {{1, 2, 3, 4}, {1, 2}, {3, 4}, {0, 4}, {}}; - for (auto i : obj.eventualSafeNodes(g1)) - printf("%d ", i); // expect: 2 4 5 6 - printf("\n"); - for (auto i : obj.eventualSafeNodes(g2)) - printf("%d ", i); // expect: 4 - printf("\n"); -} |