Solution as on 29-06-2022 80:00 pm

Author: knockcat

0207. Course Schedule.cpp

@@ -0,0 +1,42 @@
+// 207.✅ Course Schedule
+
+class Solution
+{
+public:
+    // cycle detection //  topological sort
+    bool isCycle(int sv, vector<int> adj[], vector<int> &visited)
+    {
+        if (visited[sv] == 2)
+            return true;
+
+        visited[sv] = 2;
+
+        for (auto itr : adj[sv])
+        {
+            if (visited[itr] != 1)
+                if (isCycle(itr, adj, visited))
+                    return true;
+        }
+        visited[sv] = 1;
+        return false;
+    }
+
+    bool canFinish(int numCourses, vector<vector<int>> &prerequisites)
+    {
+        vector<int> adj[numCourses];
+
+        for (auto edge : prerequisites)
+        {
+            adj[edge[1]].push_back(edge[0]);
+        }
+
+        vector<int> visited(numCourses, false);
+
+        for (int i = 0; i < numCourses; ++i)
+        {
+            if (isCycle(i, adj, visited))
+                return false;
+        }
+        return true;
+    }
+};