結果
| 問題 |
No.922 東北きりきざむたん
|
| ユーザー |
 gew1fw
|
| 提出日時 | 2025-06-12 15:25:13 |
| 言語 | PyPy3 (7.3.15) |
| 結果 |
WA
|
| 実行時間 | - |
| コード長 | 5,909 bytes |
| コンパイル時間 | 292 ms |
| コンパイル使用メモリ | 82,356 KB |
| 実行使用メモリ | 125,680 KB |
| 最終ジャッジ日時 | 2025-06-12 15:25:57 |
| 合計ジャッジ時間 | 4,749 ms |
|
ジャッジサーバーID （参考情報） |
judge4 / judge1 |
（要ログイン）
| ファイルパターン | 結果 |
|---|---|
| sample | AC * 4 |
| other | AC * 1 WA * 4 TLE * 1 -- * 20 |
ソースコード
import sys
from collections import deque
def main():
sys.setrecursionlimit(1 << 25)
N, M, Q = map(int, sys.stdin.readline().split())
edges = [[] for _ in range(N+1)]
for _ in range(M):
u, v = map(int, sys.stdin.readline().split())
edges[u].append(v)
edges[v].append(u)
# Compute connected components using BFS
visited = [False] * (N + 1)
components = []
for u in range(1, N + 1):
if not visited[u]:
q = deque()
q.append(u)
visited[u] = True
comp = []
while q:
v = q.popleft()
comp.append(v)
for nei in edges[v]:
if not visited[nei]:
visited[nei] = True
q.append(nei)
components.append(comp)
# For each component, compute parent, depth, and children
component_info = []
for comp in components:
parent = {}
depth = {}
children = {}
for u in comp:
parent[u] = -1
depth[u] = 0
children[u] = []
if not comp:
continue
root = comp[0]
q = deque()
q.append(root)
parent[root] = -1
while q:
u = q.popleft()
for v in edges[u]:
if v in parent and parent[v] == -1 and v != parent[u]:
parent[v] = u
depth[v] = depth[u] + 1
children[u].append(v)
q.append(v)
component_info.append((parent, depth, children))
# Read queries and separate within and cross
within_sum = 0
cross_queries = []
query_nodes = {}
for _ in range(Q):
a, b = map(int, sys.stdin.readline().split())
a_comp = None
b_comp = None
for i, comp in enumerate(components):
if a in comp:
a_comp = i
if b in comp:
b_comp = i
if a_comp == b_comp:
# Compute distance within component
parent_a, depth_a, children_a = component_info[a_comp]
u, v = a, b
while depth_a[u] > depth_a[v]:
u = parent_a[u]
while depth_a[v] > depth_a[u]:
v = parent_a[v]
while u != v:
u = parent_a[u]
v = parent_a[v]
lca_node = u
dist = depth_a[a] + depth_a[b] - 2 * depth_a[lca_node]
within_sum += dist
else:
cross_queries.append((a, b, a_comp, b_comp))
if a_comp not in query_nodes:
query_nodes[a_comp] = []
query_nodes[a_comp].append(a)
if b_comp not in query_nodes:
query_nodes[b_comp] = []
query_nodes[b_comp].append(b)
# Identify required components
required_components = set()
for a, b, ac, bc in cross_queries:
required_components.add(ac)
required_components.add(bc)
# Compute optimal airport for each required component
airport = {}
for comp_id in required_components:
parent, depth, children = component_info[comp_id]
nodes = components[comp_id]
q_nodes = query_nodes.get(comp_id, [])
if not q_nodes:
continue
# Build size and res
size = {u: 0 for u in nodes}
res = {u: 0 for u in nodes}
root = nodes[0]
stack = [(root, False)]
while stack:
u, processed = stack.pop()
if processed:
# Calculate size and res for u
size_u = 0
res_u = 0
if u in q_nodes:
size_u += 1
res_u += 0 # distance from u to itself is 0
for v in children[u]:
size_u += size[v]
res_u += res[v] + size[v]
size[u] = size_u
res[u] = res_u
else:
stack.append((u, True))
# Push children in reverse order to process in correct order
for v in reversed(children[u]):
stack.append((v, False))
# Pre-order traversal to update res
stack = [(root, -1)]
while stack:
u, p = stack.pop()
for v in children[u]:
# Compute res[v] based on res[u]
total = len(q_nodes)
res[v] = res[u] - size[v] + (total - size[v])
stack.append((v, u))
# Find the node with minimal res
min_res = float('inf')
best_u = root
for u in nodes:
if res[u] < min_res:
min_res = res[u]
best_u = u
airport[comp_id] = best_u
# Compute cross sum
cross_sum = 0
for a, b, ac, bc in cross_queries:
u_a = airport[ac]
u_b = airport[bc]
# Compute distance a to u_a
parent_a, depth_a, children_a = component_info[ac]
x, y = a, u_a
if depth_a[x] > depth_a[y]:
x, y = y, x
while depth_a[y] > depth_a[x]:
y = parent_a[y]
while x != y:
x = parent_a[x]
y = parent_a[y]
lca_a = x
dist_a = depth_a[a] + depth_a[u_a] - 2 * depth_a[lca_a]
# Compute distance b to u_b
parent_b, depth_b, children_b = component_info[bc]
x, y = b, u_b
if depth_b[x] > depth_b[y]:
x, y = y, x
while depth_b[y] > depth_b[x]:
y = parent_b[y]
while x != y:
x = parent_b[x]
y = parent_b[y]
lca_b = x
dist_b = depth_b[b] + depth_b[u_b] - 2 * depth_b[lca_b]
cross_sum += dist_a + dist_b
total = within_sum + cross_sum
print(total)
if __name__ == "__main__":
main()