108차 3번 문제풀이

Author: baekhangyeol

live10/test108/문제3/백한결.py

@@ -0,0 +1,33 @@
+import sys
+from collections import defaultdict
+
+sys.setrecursionlimit(10**6)
+count = 0
+
+def main():
+    input = sys.stdin.readline
+    N, W = map(int, input().split())
+
+    tree = defaultdict(list)
+
+    for _ in range(N-1):
+        u, v = map(int, input().split())
+        tree[u].append(v)
+        tree[v].append(u)
+
+    def dfs(node, parent):
+        global count
+        isLeaf = True
+        for child in tree[node]:
+            if child != parent:
+                isLeaf = False
+                dfs(child, node)
+        if isLeaf:
+            count += 1
+
+    dfs(1, -1)
+
+    print(W / count)
+
+if __name__ == '__main__':
+    main()