FilesExpand file tree

 master

/

code207.java

Copy path

Blame

More file actions

Blame

More file actions

Latest commit

 

History

History

History

49 lines (45 loc) · 1.57 KB

 master

/

code207.java

Copy path

Top

File metadata and controls

• Code
• Blame

49 lines (45 loc) · 1.57 KB

Raw

Copy raw file

Download raw file

Open symbols panel

Edit and raw actions

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

40

41

42

43

44

45

46

47

48

49

import java.util.ArrayList;

import java.util.LinkedList;

import java.util.Queue;

/*******************************************************

* Copyright (C) 2018 KEEP.COM - All Rights Reserved

*

* @Date: 2018/11/14

* @Author: fangmingfu <fangmingfu@keep.com>

* ******************************************************/

public class code207 {

class Solution {

public boolean canFinish(int numCourses, int[][] prerequisites) {

//bfs

int[] mark = new int[numCourses];

//记录依赖这个节点的数量

ArrayList[] arr = new ArrayList[numCourses];

for(int i = 0; i < arr.length; i ++){

arr[i] = new ArrayList();

}

for(int i = 0; i <prerequisites.length; i++){

arr[prerequisites[i][0]].add(prerequisites[i][1]);

mark[prerequisites[i][1]] ++;

}

int res = 0;

Queue<Integer> queue = new LinkedList<>();

for (int i = 0; i < mark.length; i ++){

if (mark[i] == 0){

queue.add(i);

res ++;

}

}

while (!queue.isEmpty()){

int i = queue.poll();

for (int j = 0; j < arr[i].size(); j++){

mark[(int) arr[i].get(j)] --;

if(mark[(Integer) arr[i].get(j)] == 0){

queue.add((Integer) arr[i].get(j));

res ++;

}

}

}

return res == numCourses;

}

}

}