제출 #1190426

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
1190426		DangKhoizzzz	Valley (BOI19_valley)	Pypy 3	0 / 100	833 ms	193180 KiB

valley

import sys
from math import log2
from collections import deque

def main():
    sys.setrecursionlimit(1 << 25)
    input = sys.stdin.read().split()
    ptr = 0

    N, S, Q, E = map(int, input[ptr:ptr+4])
    ptr +=4

    adj = [[] for _ in range(N+1)]
    edges = []
    edge_to_index = {}
    for i in range(1, N):
        A, B, W = map(int, input[ptr:ptr+3])
        ptr +=3
        adj[A].append((B, W, i))
        adj[B].append((A, W, i))
        edges.append((A, B, W))
        edge_to_index[(A, B)] = i
        edge_to_index[(B, A)] = i

    shops = set()
    for _ in range(S):
        C = int(input[ptr])
        ptr +=1
        shops.add(C)

    queries = []
    for _ in range(Q):
        I, R = map(int, input[ptr:ptr+2])
        ptr +=2
        queries.append((I, R))

    LOG = int(log2(N)) + 1
    parent = [[-1]*(N+1) for _ in range(LOG)]
    depth = [0]*(N+1)
    dist_from_root = [0]*(N+1)

    q = deque([E])
    parent[0][E] = -1
    while q:
        u = q.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_from_root[v] = dist_from_root[u] + w
                q.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] != -1 and parent[k][u] != parent[k][v]:
                u = parent[k][u]
                v = parent[k][v]
        return parent[0][u]

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

    edge_child = {}
    edge_parent = {}
    for i in range(1, N):
        A, B, W = edges[i-1]
        if depth[A] > depth[B]:
            edge_child[i] = A
            edge_parent[i] = B
        else:
            edge_child[i] = B
            edge_parent[i] = A

    closest_shop = [None]*(N+1)
    closest_dist = [float('inf')]*(N+1)

    stack = [(E, False)]
    while stack:
        node, processed = stack.pop()
        if not processed:
            stack.append((node, True))
            for neighbor, _, _ in reversed(adj[node]):
                if neighbor != parent[0][node]:
                    stack.append((neighbor, False))
        else:
            if node in shops:
                closest_shop[node] = node
                closest_dist[node] = 0
            for neighbor, _, _ in adj[node]:
                if neighbor != parent[0][node]:
                    if closest_dist[neighbor] + (distance(node, neighbor)) < closest_dist[node]:
                        closest_dist[node] = closest_dist[neighbor] + distance(node, neighbor)
                        closest_shop[node] = closest_shop[neighbor]

    # Now process queries
    for I, R in queries:
        A, B, W = edges[I-1]
        u, v = A, B
        if depth[u] > depth[v]:
            child = u
        else:
            child = v

        parent_edge = edge_parent[I]
        child_edge = edge_child[I]

        if lca(parent_edge, R) == parent_edge and lca(child_edge, R) == child_edge:
            if closest_shop[child_edge] is not None:
                print(closest_dist[child_edge] + distance(R, child_edge))
            else:
                print("oo")
        else:
            print("escaped")

if __name__ == "__main__":
    main()

컴파일 시 표준 출력 (stdout) 메시지

Compiling 'valley.py'...

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  adding: __main__.pyc (deflated 44%)

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