solved 이분 그래프 - 2436ms 317.536mb

Baekjoon/이분그래프/이분그래프_옥수빈.java

@@ -0,0 +1,60 @@
+import java.util.*;
+
+public class Main {
+
+    static List<Integer>[] connect;
+    static int[] group;
+
+    public static void main(String[] args) {
+        Scanner sc = new Scanner(System.in);
+        int K = sc.nextInt();
+        for (int i = 0; i < K; i++) {
+            int V = sc.nextInt();
+            int E = sc.nextInt();
+            connect = new List[V + 1];
+            group = new int[V + 1];
+            for (int k = 0; k <= V; k++) {
+                connect[k] = new ArrayList<>();
+            }
+            for (int j = 0; j < E; j++) {
+                int start = sc.nextInt();
+                int end = sc.nextInt();
+                connect[start].add(end);
+                connect[end].add(start);
+            }
+            boolean answer = true;
+            for (int j = 1; j <= V; j++) {
+                if (group[j] == 0) {
+                    if (!BFS(j)) {
+                        answer = false;
+                        break;
+                    }
+                }
+            }
+            if (answer)
+                System.out.println("YES");
+            else
+                System.out.println("NO");
+        }
+    }
+
+    static boolean BFS(int n) {
+        boolean[] visited = new boolean[connect.length];
+        Queue<Integer> queue = new LinkedList<>();
+        queue.add(n);
+        group[n] = 1;
+        while (!queue.isEmpty()) {
+            int x = queue.poll();
+            visited[x] = true;
+            int g = group[x];
+            for (int c : connect[x]) {
+                if (group[c] != 0 && group[c] == g)
+                    return false;
+                group[c] = -g;
+                if (!visited[c])
+                    queue.add(c);
+            }
+        }
+        return true;
+    }
+}