Create CourseSchedule-I.cpp

Graphs/CourseSchedule-I.cpp

@@ -0,0 +1,39 @@
+class Solution {
+public:
+    bool canFinish(int numCourses, vector<vector<int>>& prerequisites) {
+         vector<int>adj[numCourses];
+	    for(auto i:prerequisites){
+	        adj[i[0]].push_back(i[1]);
+	    }
+	        vector<int>indegree(numCourses,0);
+	        for(int i=0;i<numCourses;i++){
+	            for(auto it:adj[i]){
+	                indegree[it]++;
+	            }
+	        }
+	        queue<int>q;
+	        for(int i=0;i<numCourses;i++){
+	            if(indegree[i]==0){
+	                q.push(i);
+	            }
+	        }
+	        vector<int>topo;
+	        while(!q.empty()){
+	            int node=q.front();
+	            q.pop();
+	            topo.push_back(node);
+
+	            for(auto it:adj[node]){
+	                indegree[it]--;
+	                if(indegree[it]==0){
+	                    q.push(it);
+	                }
+	            }
+	        }
+
+	    if(topo.size()==numCourses){
+	        return true;
+	    }
+	    return false;
+    }
+};