和207 Course Schedule是一样的

1     public int[] findOrder(int numCourses, int[][] prerequisites) { 2         int[] result = new int[numCourses]; 3         if(numCourses < 1) { 4             return new int[0]; 5         } 6         int index = numCourses - 1; 7         Queue
     
       queue = new LinkedList
      
       (); 8         int[] indegree = new int[numCourses]; 9         int len = prerequisites.length;10         for(int i = 0; i < len; i++) {11             indegree[prerequisites[i][1]]++;12         }13         for(int i = 0; i < numCourses; i++) {14             if(indegree[i] == 0) {15                 queue.offer(i);16             } 17         }18         while(!queue.isEmpty()) {19             int cur = queue.poll();20             result[index] = cur;21             index--;22             for(int i = 0; i < len; i++) {23                 if(prerequisites[i][0] == cur) {24                     indegree[prerequisites[i][1]]--;25                     if(indegree[prerequisites[i][1]] == 0) {26                         queue.add(prerequisites[i][1]);27                     }28                 }29             }30         }31         for(int i = 0; i < numCourses; i++) {32             if(indegree[i] != 0) {33                 return new int[0];34             }35         }36         return result;37     }