-
Notifications
You must be signed in to change notification settings - Fork 0
/
BipartiteGraph.java
90 lines (66 loc) · 2.61 KB
/
BipartiteGraph.java
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
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.*;
import java.util.Queue;
public class BipartiteGraph {
private static List<List<Integer>> resultList;
private static int[] colorArr;
public static void main(String[] args) throws Exception {
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
StringBuffer sb = new StringBuffer();
StringTokenizer st;
int K = Integer.parseInt(br.readLine()); // testCase
for(int testCase = 0; testCase < K; testCase++) {
st = new StringTokenizer(br.readLine(), " ");
int V = Integer.parseInt(st.nextToken()); // node
int E = Integer.parseInt(st.nextToken()); // edge
initResultList(V);
initColorArr(V);
for(int edge = 0; edge < E; edge++) {
st = new StringTokenizer(br.readLine(), " ");
int u = Integer.parseInt(st.nextToken());
int v = Integer.parseInt(st.nextToken());
resultList.get(u).add(v);
resultList.get(v).add(u);
}
boolean isPartial = false;
for(int nodeNumber = 1; nodeNumber < resultList.size(); nodeNumber++) {
if(colorArr[nodeNumber] == 0) {
isPartial = checkValidation(nodeNumber, 1);
}
if(!isPartial) break;
}
if(!isPartial) {
sb.append("NO").append("\n");
continue;
}
sb.append("YES").append("\n");
}
System.out.println(sb);
}
private static void initResultList(int length) {
resultList = new ArrayList<>(length + 1);
for(int index = 0; index <= length; index++) {
resultList.add(new LinkedList<>());
}
}
private static void initColorArr(int length) {
colorArr = new int[length + 1];
}
private static boolean checkValidation(int startNumber, int color) {
Queue<Integer> resultQueue = new LinkedList<>();
resultQueue.add(startNumber);
colorArr[startNumber] = color;
while(!resultQueue.isEmpty()) {
int currentNumber = resultQueue.poll();
for(int nextNumber : resultList.get(currentNumber)) {
if(colorArr[currentNumber] == colorArr[nextNumber]) return false;
if(colorArr[nextNumber] == 0) {
colorArr[nextNumber] = colorArr[currentNumber] * -1;
resultQueue.add(nextNumber);
}
}
}
return true;
}
}