add cpp solution

Author: jinshendan

July-LeetCoding-Challenge/18-Course-Schedule-II/Course-Schedule-II.cpp

@@ -0,0 +1,29 @@
+class Solution {
+public:
+    
+    vector<int> findOrder(int numCourses, vector<vector<int>>& prerequisites) {
+        vector<int> deg(numCourses, 0);
+        vector<vector<int>> G(numCourses, vector<int>());
+        for (auto v: prerequisites){
+            deg[v[0]] ++;
+            G[v[1]].push_back(v[0]);
+        }
+        
+
+        queue<int> q;
+        for (int i = 0; i < numCourses; i++) if (!deg[i]) q.push(i);
+
+        vector<int> ans;
+        while(!q.empty()){
+            int i = q.front(); q.pop();
+            ans.push_back(i);
+            for (auto j: G[i]){
+                deg[j]--;
+                if (!deg[j]) q.push(j);
+            }
+        }
+
+        if (ans.size() == numCourses) return ans;
+        return vector<int>();       
+    }
+};