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1 | 1 | classSolution { |
2 | 2 | publicList<Boolean>checkIfPrerequisite(intnumCourses,int[][]prerequisites,int[][]queries) { |
3 | | - |
4 | | - |
5 | 3 | HashMap<Integer,List<Integer>>hm =newHashMap<>(); |
6 | 4 | List<Boolean>res =newArrayList<>(); |
7 | 5 | boolean[]visited =newboolean[numCourses]; |
8 | | -for(inti=0;i<prerequisites.length;i++) { |
| 6 | +for(inti =0;i <prerequisites.length;i++) { |
9 | 7 | hm.putIfAbsent(prerequisites[i][1],newArrayList<>()); |
10 | 8 | hm.get(prerequisites[i][1]).add(prerequisites[i][0]); |
11 | 9 | } |
12 | | -for(inti=0;i<queries.length;i++) { |
| 10 | +for(inti =0;i <queries.length;i++) { |
13 | 11 | visited =newboolean[numCourses]; |
14 | 12 | res.add(dfs(hm,queries[i][1],queries[i][0],visited)); |
15 | 13 | } |
16 | 14 | returnres; |
17 | | - |
18 | 15 | } |
19 | 16 |
|
20 | 17 | booleandfs(HashMap<Integer,List<Integer>>hm,ints,inttarget,boolean[]visited) { |
| 18 | +if (!hm.containsKey(s))returnfalse; |
| 19 | +if (hm.get(s).contains(target))returntrue; |
21 | 20 |
|
22 | | -if(!hm.containsKey(s))returnfalse; |
23 | | -if(hm.get(s).contains(target))returntrue; |
24 | | - |
25 | | -for(inti:hm.get(s)) { |
26 | | -if(visited[i])continue; |
| 21 | +for (inti:hm.get(s)) { |
| 22 | +if (visited[i])continue; |
27 | 23 | visited[i] =true; |
28 | | -if(dfs(hm,i,target,visited))returntrue; |
| 24 | +if(dfs(hm,i,target,visited))returntrue; |
29 | 25 | } |
30 | 26 | returnfalse; |
31 | 27 | } |
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