結果

問題 No.1094 木登り / Climbing tree
ユーザー lam6er
提出日時 2025-03-20 21:00:47
言語 PyPy3
(7.3.15)
結果
AC  
実行時間 983 ms / 2,000 ms
コード長 1,791 bytes
コンパイル時間 295 ms
コンパイル使用メモリ 82,396 KB
実行使用メモリ 215,520 KB
最終ジャッジ日時 2025-03-20 21:01:16
合計ジャッジ時間 24,286 ms
ジャッジサーバーID
（参考情報） 		judge5 / judge3
このコードへのチャレンジ
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ファイルパターン 結果
sample AC * 1
other AC * 26
権限があれば一括ダウンロードができます

ソースコード

diff #
プレゼンテーションモードにする

import sys
from collections import deque
def main():
    sys.setrecursionlimit(1 << 25)
    input = sys.stdin.read().split()
    ptr = 0
    n = int(input[ptr])
    ptr +=1
    adj = [[] for _ in range(n+1)]
    for _ in range(n-1):
        a = int(input[ptr])
        b = int(input[ptr+1])
        c = int(input[ptr+2])
        ptr +=3
        adj[a].append( (b, c) )
        adj[b].append( (a, c) )
    LOG = 20
    parent = [0]*(n+1)
    depth = [0]*(n+1)
    distance = [0]*(n+1)
    root =1
    parent[root] =0
    q = deque([root])
    while q:
        u = q.popleft()
        for v, w in adj[u]:
            if parent[u] == v:
                continue
            if parent[v] ==0 and v != root:
                parent[v] =u
                depth[v] = depth[u]+1
                distance[v] = distance[u] + w
                q.append(v)
    up = [[0]*(n+1) for _ in range(LOG)]
    for u in range(1, n+1):
        up[0][u] = parent[u]
    for k in range(1, LOG):
        for u in range(1, n+1):
            up[k][u] = up[k-1][up[k-1][u]]
    def lca(u, v):
        if depth[u] < depth[v]:
            u, v = v, u
        for k in range(LOG-1, -1, -1):
            if depth[u] - (1 << k) >= depth[v]:
                u = up[k][u]
        if u ==v:
            return u
        for k in range(LOG-1, -1, -1):
            if up[k][u] != up[k][v]:
                u = up[k][u]
                v = up[k][v]
        return up[0][u]
    q_num = int(input[ptr])
    ptr +=1
    output = []
    for _ in range(q_num):
        s = int(input[ptr])
        t = int(input[ptr+1])
        ptr +=2
        lca_node = lca(s, t)
        res = distance[s] + distance[t] - 2 * distance[lca_node]
        output.append(str(res))
    print('\n'.join(output))
if __name__ == '__main__':
    main()
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