[bzoj] 3757: 苹果树

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题意

一棵树上每个节点都有颜色,每次回答树链上有几种颜色,有时询问视两种颜色为同一种颜色

传送门

分析

莫队算法

代码

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#include <cstdio>
#define Rep(i,l,r) for(i=(l);i<=(r);i++)
#define Rev(i,r,l) for(i=(r);i>=(l);i--)
int CH , NEG ;
template <typename TP>
inline void read(TP& ret) {
    ret = NEG = 0 ; while (CH=getchar() , CH<'!') ;
    if (CH == '-') NEG = true , CH = getchar() ;
    while (ret = ret*10+CH-'0' , CH=getchar() , CH>'!') ;
    if (NEG) ret = -ret ;
}
template <typename TP>
inline void reads(TP& ret) {
truewhile (ret=getchar() , ret<'!') ;
truewhile (CH=getchar() , CH>'!') ;
}

#include <algorithm>
#include <cmath>

#define  maxn  50010LL
#define  maxm  50010LL
#define  maxq  100010LL
#define  maxk  17LL

struct FST { int to , next ; } e[maxm<<1] ;
int star[maxn] = {0} , tote = 1 ;
void AddEdge(int u , int v) { e[++tote].to = v ; e[tote].next = star[u] ; star[u] = tote ; }

int n , m , root , ansnow ;
int cntblc , szblc , idx , top ;

int col[maxn] , cnt[maxn] = {0} ;
int dfn[maxn] , sta[maxn] , belong[maxn] , dep[maxn] , size[maxn] , par[maxn][maxk] ;
int ans[maxq] ;
bool vis[maxn] = {0} ;

struct QUERY {
trueint u , v , a , b , id ;
truebool operator < (const QUERY& b) const
true{ return belong[u]==belong[b.u]? dfn[v]<dfn[b.v] : belong[u]<belong[b.u] ; }
} q[maxq] ;

void dfs(int u , int fa) {
int v , p ;
truesta[++top] = u ;
truepar[u][0] = fa ;
truedfn[u] = ++idx ;
truedep[u] = dep[fa]+1 ;
truesize[u] = 0 ;
truefor (p = star[u] ; p ; p = e[p].next)
truetrueif (v=e[p].to , v!=fa) {
truetruetruedfs(v , u) ;
truetruetruesize[u] += size[v] ;
truetruetrueif (size[u] >= szblc) {
truetruetruetruesize[u] = 0 ;
truetruetruetruecntblc ++ ;
truetruetruetruewhile (sta[top] != u) belong[sta[top--]] = cntblc ;
truetruetrue}
truetrue}
truesize[u] ++ ;
}

void ST() {
int i , k ;
trueRep (k,1,maxk-1)
truetrueRep (i,1,n)
truetruetruepar[i][k] = par[par[i][k-1]][k-1] ;
}

int LCA(int u , int v) {
trueint k ;
trueif (dep[u] < dep[v]) std::swap(u,v) ;
trueRev (k,maxk-1,0)
truetrueif (dep[par[u][k]] >= dep[v]) u = par[u][k] ;
trueif (u == v) return u ;
trueRev (k,maxk-1,0)
truetrueif (par[u][k] != par[v][k])
truetruetrueu = par[u][k] , v = par[v][k] ;
truereturn par[u][0] ;
}

void Reverse(int u) {
trueif (!vis[u]) { vis[u]=true;cnt[col[u]]++;if(cnt[col[u]]==1)ansnow++; }
trueelse { vis[u]=false;cnt[col[u]]--;if(cnt[col[u]]==0)ansnow--; }
}

void MoveTo(int u,int v) {
truewhile (u != v)
truetrueif (dep[u] > dep[v]) Reverse(u) , u = par[u][0] ;
truetrueelse Reverse(v) , v = par[v][0] ;
}

void GetAns(int i , int lca) {
trueReverse(lca) ;
trueans[q[i].id] = ansnow ;
trueif (q[i].a!=q[i].b && cnt[q[i].a] && cnt[q[i].b]) ans[q[i].id] -- ;
trueReverse(lca) ;
}

int main() {
int i , u , v , lca ;
//	#define READ
true#ifdef  READ
truetruefreopen(".in" ,"r",stdin ) ;
truetruefreopen(".out","w",stdout) ;
true#endif
trueread(n) , read(m) ;
trueif (n < 5) szblc = n ;
trueelse szblc = (int)pow(n,2.0/3.0) ;
trueRep (i,1,n) read(col[i]) ;
trueRep (i,1,n) {
truetrueread(u) , read(v) ;
truetrueif (!u) root = v ;
truetrueelse if (!v) root = u ;
truetrueelse AddEdge(u,v) , AddEdge(v,u) ;
true}
truecntblc = idx = dep[0] = ansnow = top = 0 ;
truedfs(root,0) ;
truecntblc ++ ;
truewhile (top) belong[sta[top--]] = cntblc ;
trueST() ;
trueRep (i,1,m) {
truetrueread(u) , read(v) ;
truetrueif (belong[u] > belong[v]) std::swap(u,v) ;
truetrueq[i].u = u , q[i].v= v ;
truetrueread(q[i].a) , read(q[i].b) ;
truetrueq[i].id = i ;
true}
truestd::sort(q+1,q+m+1) ;
truelca = LCA(q[1].u,q[1].v) ;
trueMoveTo(q[1].u,q[1].v) ;
trueGetAns(1,lca) ;
trueRep (i,2,m) {
truetrueMoveTo(q[i-1].u,q[i].u) ;
truetrueMoveTo(q[i-1].v,q[i].v) ;
truetruelca = LCA(q[i].u,q[i].v) ;
truetrueGetAns(i,lca) ;
true}
trueRep (i,1,m) printf("%d\n", ans[i]) ;
true#ifdef  READ
truetruefclose(stdin) ; fclose(stdout) ;
true#else
truetruegetchar() ; getchar() ;
true#endif
truereturn 0 ;
}

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