結果

問題 No.1212 Second Path
コンテスト
ユーザー qwewe
提出日時 2025-04-24 12:32:43
言語 PyPy3
(7.3.15)
結果
TLE  
実行時間 -
コード長 3,292 bytes
コンパイル時間 212 ms
コンパイル使用メモリ 82,204 KB
実行使用メモリ 471,488 KB
最終ジャッジ日時 2025-04-24 12:34:09
合計ジャッジ時間 10,549 ms
ジャッジサーバーID
（参考情報） 		judge1 / judge4
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 -- * 3
other TLE * 1 -- * 44
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
from sys import stdin
from collections import defaultdict, deque

sys.setrecursionlimit(1 << 25)

def main():
    input = sys.stdin.read().split()
    ptr = 0
    N = int(input[ptr])
    ptr +=1
    edges = []
    adj = [[] for _ in range(N+1)]
    for _ in range(N-1):
        u = int(input[ptr])
        v = int(input[ptr+1])
        w = int(input[ptr+2])
        ptr +=3
        edges.append((u, v, w))
        adj[u].append((v, w))
        adj[v].append((u, w))
    
    LOG = 20
    parent = [[-1]*(N+1) for _ in range(LOG)]
    depth = [0]*(N+1)
    dist_root = [0]*(N+1)
    queue = deque([1])
    parent[0][1] = -1
    while queue:
        u = queue.popleft()
        for v, w in adj[u]:
            if parent[0][v] == -1 and v != parent[0][u]:
                parent[0][v] = u
                depth[v] = depth[u] +1
                dist_root[v] = dist_root[u] + w
                queue.append(v)
    
    for k in range(1, LOG):
        for v in range(1, N+1):
            if parent[k-1][v] != -1:
                parent[k][v] = parent[k-1][parent[k-1][v]]
    
    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 = parent[k][u]
        if u == v:
            return u
        for k in range(LOG-1, -1, -1):
            if parent[k][u] != parent[k][v]:
                u = parent[k][u]
                v = parent[k][v]
        return parent[0][u]
    
    def get_path(u, a):
        path = []
        while u != a:
            for v, w in adj[u]:
                if depth[v] == depth[u] -1:
                    path.append((u, v, w))
                    u = v
                    break
        return path
    
    edge_set = set()
    for u, v, w in edges:
        if u > v:
            u, v = v, u
        edge_set.add((u, v, w))
    
    edge_dict = dict()
    for u, v, w in edges:
        if u > v:
            u, v = v, u
        edge_dict[(u, v)] = w
    
    Q = int(input[ptr])
    ptr +=1
    for _ in range(Q):
        x = int(input[ptr])
        y = int(input[ptr+1])
        ptr +=2
        if x == y:
            print(0)
            continue
        a = lca(x, y)
        path_x = get_path(x, a)
        path_y = get_path(y, a)
        path = []
        path.extend(path_x)
        path_y_rev = []
        for p in reversed(path_y):
            u, v, w = p
            path_y_rev.append((v, u, w))
        path.extend(path_y_rev)
        S = set()
        nodes = set()
        nodes.add(a)
        for u, v, w in path:
            if u < v:
                S.add((u, v, w))
            else:
                S.add((v, u, w))
            nodes.add(u)
            nodes.add(v)
        min_w = float('inf')
        for u, v, w in edges:
            if u < v:
                key = (u, v)
            else:
                key = (v, u)
            e = (min(u, v), max(u, v), w)
            if e not in S:
                if u in nodes or v in nodes:
                    if w < min_w:
                        min_w = w
        if min_w == float('inf'):
            print(-1)
        else:
            D = 0
            for u, v, w in path:
                D += w
            print(D + 2 * min_w)

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