結果
問題 | No.2337 Equidistant |
ユーザー |
![]() |
提出日時 | 2023-06-02 22:09:23 |
言語 | PyPy3 (7.3.15) |
結果 |
AC
|
実行時間 | 2,944 ms / 4,000 ms |
コード長 | 4,018 bytes |
コンパイル時間 | 629 ms |
コンパイル使用メモリ | 82,432 KB |
実行使用メモリ | 242,316 KB |
最終ジャッジ日時 | 2024-12-28 18:24:09 |
合計ジャッジ時間 | 35,888 ms |
ジャッジサーバーID (参考情報) |
judge1 / judge2 |
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ファイルパターン | 結果 |
---|---|
sample | AC * 1 |
other | AC * 28 |
ソースコード
class JumpOnTree:def __init__(self, edges, root=0):self.n = len(edges)self.edges = edgesself.root = rootself.logn = (self.n - 1).bit_length()self.depth = [-1] * self.nself.depth[self.root] = 0self.parent = [[-1] * self.n for _ in range(self.logn)]self.dfs()self.doubling()def dfs(self):stack = [self.root]while stack:u = stack.pop()for v in self.edges[u]:if self.depth[v] == -1:self.depth[v] = self.depth[u] + 1self.parent[0][v] = ustack.append(v)def doubling(self):for i in range(1, self.logn):for u in range(self.n):p = self.parent[i - 1][u]if p != -1:self.parent[i][u] = self.parent[i - 1][p]def lca(self, u, v):du = self.depth[u]dv = self.depth[v]if du > dv:du, dv = dv, duu, v = v, ud = dv - dui = 0while d > 0:if d & 1:v = self.parent[i][v]d >>= 1i += 1if u == v:return ulogn = (du - 1).bit_length()for i in range(logn - 1, -1, -1):pu = self.parent[i][u]pv = self.parent[i][v]if pu != pv:u = puv = pvreturn self.parent[0][u]def dist(self,u,v):L=self.lca(u,v)return self.depth[u]+self.depth[v]-self.depth[L]*2def jump(self, u, v, k):if k == 0:return up = self.lca(u, v)d1 = self.depth[u] - self.depth[p]d2 = self.depth[v] - self.depth[p]if d1 + d2 < k:return -1if k <= d1:d = kelse:u = vd = d1 + d2 - ki = 0while d > 0:if d & 1:u = self.parent[i][u]d >>= 1i += 1return ufrom sys import stdininput=lambda :stdin.readline()[:-1]n,q=map(int,input().split())edge=[[] for i in range(n)]for i in range(n-1):a,b=map(lambda x:int(x)-1,input().split())edge[a].append(b)edge[b].append(a)JT=JumpOnTree(edge)query=[[] for i in range(n)]for i in range(q):s,t=map(lambda x:int(x)-1,input().split())d=JT.dist(s,t)if d%2:continuemid=JT.jump(s,t,d//2)ng1=JT.jump(mid,s,1)ng2=JT.jump(mid,t,1)query[mid].append((i,ng1,ng2))def rerooting(query):dp=[[E]*len(edge[v]) for v in range(n)]# dfs1memo=[E]*nfor v in order[::-1]:res=Efor i in range(len(edge[v])):if edge[v][i]==par[v]:continuedp[v][i]=memo[edge[v][i]]res=merge(res,f(dp[v][i],edge[v][i]))memo[v]=g(res,v)# dfs2memo2=[E]*nfor v in order:for i in range(len(edge[v])):if edge[v][i]==par[v]:dp[v][i]=memo2[v]s=len(edge[v])cumR=[E]*(s+1)cumR[s]=Efor i in range(s,0,-1):cumR[i-1]=merge(cumR[i],f(dp[v][i-1],edge[v][i-1]))cumL=Efor i in range(s):if edge[v][i]!=par[v]:val=merge(cumL,cumR[i+1])memo2[edge[v][i]]=g(val,v)cumL=merge(cumL,f(dp[v][i],edge[v][i]))ans=[0]*qfor v in range(n):if query[v]:dic={}for i in range(len(edge[v])):dic[edge[v][i]]=dp[v][i]for i,ng1,ng2 in query[v]:res=nres-=dic[ng1]res-=dic[ng2]ans[i]=resreturn ansE=0def f(res,v):return resdef g(res,v):return res+1def merge(a,b):return a+bdef calc_ans(res,v):return g(res,v)# make order table# root = 0from collections import dequeorder=[]par=[-1]*ntodo=deque([0])while todo:v=todo.popleft()order.append(v)for u in edge[v]:if u!=par[v]:par[u]=vtodo.append(u)ans=rerooting(query)print(*ans,sep='\n')