結果

問題 No.901 K-ary εxtrεεmε
コンテスト
ユーザー lam6er
提出日時 2025-03-31 17:20:40
言語 PyPy3
(7.3.15)
結果
AC  
実行時間 512 ms / 3,000 ms
コード長 2,499 bytes
コンパイル時間 157 ms
コンパイル使用メモリ 82,656 KB
実行使用メモリ 136,020 KB
最終ジャッジ日時 2025-03-31 17:21:23
合計ジャッジ時間 14,609 ms
ジャッジサーバーID
（参考情報） 		judge5 / judge2
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 * 29
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 # 

import sys
sys.setrecursionlimit(1 << 25)

def main():
    data = sys.stdin.read().split()
    ptr = 0
    N = int(data[ptr])
    ptr += 1
    adj = [[] for _ in range(N)]
    for _ in range(N-1):
        u = int(data[ptr])
        v = int(data[ptr+1])
        w = int(data[ptr+2])
        adj[u].append((v, w))
        adj[v].append((u, w))
        ptr +=3

    # Preprocessing for in_time, depth, parent, dist
    in_time = [0] * N
    depth = [0] * N
    parent = [-1] * N
    dist = [0] * N
    visited = [False] * N
    stack = [(0, -1, 0)]  # (node, parent, weight_from_parent)
    time = 0

    while stack:
        u, p, w = stack.pop()
        if visited[u]:
            continue
        visited[u] = True
        in_time[u] = time
        time += 1
        if p != -1:
            dist[u] = dist[p] + w
            depth[u] = depth[p] + 1
        else:
            dist[u] = 0
            depth[u] = 0
        parent[u] = p
        # Push children in reverse order to process in correct DFS order
        for v, edge_w in reversed(adj[u]):
            if not visited[v] and v != p:
                stack.append((v, u, edge_w))

    # Preprocess LCA binary lifting table
    LOG = 20
    up = [[-1]*N for _ in range(LOG)]
    for i in range(N):
        up[0][i] = parent[i]
    for k in range(1, LOG):
        for i in range(N):
            if up[k-1][i] != -1:
                up[k][i] = up[k-1][ up[k-1][i] ]

    def lca(u, v):
        if depth[u] < depth[v]:
            u, v = v, u
        # Bring u to the depth of v
        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]

    def get_distance(u, v):
        ancestor = lca(u, v)
        return dist[u] + dist[v] - 2 * dist[ancestor]

    Q = int(data[ptr])
    ptr +=1
    for _ in range(Q):
        k_i = int(data[ptr])
        ptr +=1
        x_list = list(map(int, data[ptr:ptr + k_i]))
        ptr +=k_i
        if k_i == 1:
            print(0)
            continue
        # Sort by in_time
        x_list.sort(key=lambda x: in_time[x])
        total = 0
        K = len(x_list)
        for i in range(K):
            u = x_list[i]
            v = x_list[(i+1)%K]
            total += get_distance(u, v)
        print(total // 2)

if __name__ == "__main__":
    main()
0