116차 1번 문제풀이

Author: hangyeol

live11/test116/문제1/백한결.py

@@ -0,0 +1,47 @@
+import sys
+sys.setrecursionlimit(10**6)
+
+def main():
+    input = sys.stdin.readline
+    T = int(input())
+
+    for _ in range(T):
+        N = int(input())
+        parent = [0] * (N+1)
+        depth = [0] * (N+1)
+        tree = [[] for _ in range(N+1)]
+        isChild = [False] * (N+1)
+        for _ in range(N-1):
+            a, b = map(int, input().split())
+            parent[b] = a
+            tree[a].append(b)
+            isChild[b] = True
+
+        root = 0
+        for i in range(1, N+1):
+            if not isChild[i]:
+                root = i
+                break
+
+        def dfs(node, d):
+            depth[node] = d
+            for child in tree[node]:
+                dfs(child, d + 1)
+
+        dfs(root, 0)
+
+        a, b = map(int, input().split())
+
+        while depth[a] > depth[b]:
+            a = parent[a]
+        while depth[a] < depth[b]:
+            b = parent[b]
+
+        while a != b:
+            a = parent[a]
+            b = parent[b]
+
+        print(a)
+
+if __name__ == '__main__':
+    main()