leetcode

Author: Ashish-kumar7

Diff for: leetcode-com-explore-challenge-card-july-leetcoding-challenge-546-week-3-july-15th-july-21st-3394.cpp

@@ -0,0 +1,31 @@
+class Solution {
+public:
+    vector<int> findOrder(int numCourses, vector<vector<int>>& prerequisites) {
+        
+       vector<int> order;
+        stack<int> dfs;
+        int count = 0;
+        vector<int> indegree(numCourses,0);
+        for(int i=0; i<prerequisites.size(); i++) {
+            indegree[prerequisites[i][0]]++;
+        }
+        for(int i=0; i<indegree.size(); i++) {
+            if(indegree[i]==0)
+                dfs.push(i);
+        }
+        while(!dfs.empty()) {
+            int current = dfs.top(); dfs.pop();
+            order.push_back(current);
+            count++;
+            for(int i=0; i<prerequisites.size(); i++) {
+                if(prerequisites[i][1]==current) {
+                    indegree[prerequisites[i][0]]--;
+                    if(indegree[prerequisites[i][0]]==0)
+                        dfs.push(prerequisites[i][0]);
+                }
+            }
+        }
+        if(count != numCourses) order.clear();
+        return order;
+    }
+};