[Luogu 2486] SDOI2011 染色
树剖水题，线段树维护。
详细题解不写了。
我只想说我写的线段树又变漂亮了qwq
#include <algorithm>
#include <cstdio>
#include <cstring>
const int MAXN=100010;
int n,m;
class HLD
{
private:
bool vis[MAXN];
int num;
static int rank[MAXN];
static struct Node
{
int v,depth,father,son,top,size,DFN;
}s[MAXN];
class SegmentTree
{
private:
struct Node
{
int v,left,right,lazy,color[2];
Node *c[2];
Node(int l,int r):left(l),right(r),lazy(0)
{
memset(color,0,sizeof color);
c[0]=c[1]=nullptr;
if(l==r)
{
v=1;
color[0]=color[1]=s[rank[l]].v;
return;
}
int mid=l+r>>1;
c[0]=new Node(l,mid);
c[1]=new Node(mid+1,r);
PushUp();
}
~Node(void)
{
if(c[0]!=nullptr)
delete c[0];
if(c[1]!=nullptr)
delete c[1];
}
void Modify(int x)
{
v=1;
lazy=color[0]=color[1]=x;
}
void PushUp(void)
{
v=c[0]->v+c[1]->v;
color[0]=c[0]->color[0];
color[1]=c[1]->color[1];
if(c[0]->color[1]==c[1]->color[0])
--v;
}
void PushDown(void)
{
if(c[0]!=nullptr)
c[0]->Modify(lazy);
if(c[1]!=nullptr)
c[1]->Modify(lazy);
lazy=0;
}
int Color(int x)
{
if(left==right)
return color[0];
if(lazy)
PushDown();
int mid=left+right>>1;
if(x>mid)
return c[1]->Color(x);
else
return c[0]->Color(x);
}
void Change(int l,int r,int v)
{
if(l==left && r==right)
{
Modify(v);
return;
}
if(lazy)
PushDown();
int mid=left+right>>1;
if(r<=mid)
c[0]->Change(l,r,v);
else if(l>mid)
c[1]->Change(l,r,v);
else
{
c[0]->Change(l,mid,v);
c[1]->Change(mid+1,r,v);
}
PushUp();
}
int Query(int l,int r)
{
if(l==left && r==right)
return v;
int mid=left+right>>1;
if(lazy)
PushDown();
if(r<=mid)
return c[0]->Query(l,r);
else if(l>mid)
return c[1]->Query(l,r);
else
{
int ans=c[0]->Query(l,mid)+c[1]->Query(mid+1,r);
if(c[0]->color[1]==c[1]->color[0])
--ans;
return ans;
}
}
}*root;
public:
SegmentTree(int n)
{
root=new Node(1,n);
}
~SegmentTree(void)
{
delete root;
}
int Color(int x)
{
return root->Color(x);
}
void Change(int l,int r,int v)
{
root->Change(l,r,v);
}
int Query(int l,int r)
{
return root->Query(l,r);
}
}*T;
struct Edge
{
int to;
Edge *next;
Edge(int to,Edge* next):to(to),next(next){}
~Edge(void)
{
if(next!=nullptr)
delete next;
}
}*head[MAXN];
void AddEdges(int u,int v)
{
head[u]=new Edge(v,head[u]);
head[v]=new Edge(u,head[v]);
}
void DFS1(int u,int k)
{
s[u].depth=k;
s[u].size=1;
int v;
for(Edge *i=head[u];i!=nullptr;i=i->next)
if(!s[v=i->to].size)
{
DFS1(v,k+1);
s[v].father=u;
s[u].size+=s[v].size;
if(s[v].size>s[s[u].son].size)
s[u].son=v;
}
}
void DFS2(int u,int top)
{
s[u].top=top;
s[u].DFN=++num;
rank[num]=u;
vis[u]=true;
if(s[u].son)
DFS2(s[u].son,top);
int v;
for(Edge *i=head[u];i!=nullptr;i=i->next)
if(!vis[v=i->to])
DFS2(v,v);
}
public:
HLD(int n):num(0)
{
memset(s,0,sizeof s);
std::fill(head+1,head+n+1,nullptr);
for(int i=1;i<=n;++i)
scanf("%d",&s[i].v);
for(int i=1,u,v;i<n;++i)
{
scanf("%d %d",&u,&v);
AddEdges(u,v);
}
DFS1(1,1);
DFS2(1,1);
T=new SegmentTree(n);
}
~HLD(void)
{
for(int i=1;i<=n;++i)
delete head[i];
delete T;
}
void Change(int x,int y)
{
int a,b,v;
scanf("%d",&v);
while((a=s[x].top)^(b=s[y].top))
if(s[a].depth>s[b].depth)
{
T->Change(s[a].DFN,s[x].DFN,v);
x=s[a].father;
}
else
{
T->Change(s[b].DFN,s[y].DFN,v);
y=s[b].father;
}
if(s[x].depth<s[y].depth)
T->Change(s[x].DFN,s[y].DFN,v);
else
T->Change(s[y].DFN,s[x].DFN,v);
}
void Query(int x,int y)
{
int a,b,ans=0;
while((a=s[x].top)^(b=s[y].top))
if(s[a].depth>s[b].depth)
{
ans+=T->Query(s[a].DFN,s[x].DFN);
x=s[a].father;
if(T->Color(s[a].DFN)==T->Color(s[x].DFN))
--ans;
}
else
{
ans+=T->Query(s[b].DFN,s[y].DFN);
y=s[b].father;
if(T->Color(s[b].DFN)==T->Color(s[y].DFN))
--ans;
}
ans+=s[x].depth<s[y].depth ? T->Query(s[x].DFN,s[y].DFN) : T->Query(s[y].DFN,s[x].DFN);
printf("%d
",ans);
}
}*T;
int HLD::rank[MAXN];
HLD::Node HLD::s[MAXN];
int main(int argc,char** argv)
{
scanf("%d %d",&n,&m);
T=new HLD(n);
char c;
for(int i=1,x,y;i<=m;++i)
{
scanf("
%c %d %d",&c,&x,&y);
if(c=='C')
T->Change(x,y);
else
T->Query(x,y);
}
delete T;
return 0;
}
谢谢阅读。