• 최소 공통 조상 (Lowest Common Ancestor / LCA) 쿼리를 처리하는 가장 기본적인 형태의 문제. LCA 2의 쉬운 버전이다. 코드는 그쪽과 동일한 코드를 제출했다.

"""Solution code for "BOJ 11437. LCA".

- Problem link: https://www.acmicpc.net/problem/11437
- Solution link: http://www.teferi.net/ps/problems/boj/11437

Tags: [LCA]
"""

import sys
from teflib import tree as ttree

ROOT = 0


def main():
    N = int(sys.stdin.readline())
    tree = [[] for _ in range(N)]
    for _ in range(N - 1):
        u, v = [int(x) for x in sys.stdin.readline().split()]
        tree[u - 1].append(v - 1)
        tree[v - 1].append(u - 1)

    lca = ttree.LowestCommonAncestor(tree, ROOT)
    M = int(sys.stdin.readline())
    for _ in range(M):
        u, v = [int(x) for x in sys.stdin.readline().split()]
        print(lca.lca_node(u - 1, v - 1) + 1)


if __name__ == '__main__':
    main()

• Dependency: teflib.tree.LowestCommonAncestor