bzoj2157 旅游 树链剖分

4000
其实就是个树链剖分，但是变成了边权而已，把边权移到他深度更大的端点上就行了。问题是操作太多了，而且还有个改变权值和取反我还要单独拉出来打。。打了半个小时，，编译调了半天，6000多B，都不想肉眼检查结果1A了。。有点窃喜。。

注意取反哪里的最大最小值的维护，要倒过来。

#include<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>
#define fo(i,a,b) for(int i=a;i<=b;i++)
#define fd(i,a,b) for(int i=a;i>=b;i--)
using namespace std;
const int N=5e5+5;
const int inf=2147483646;
int head
,next
,go
,val
,n;
int size
,son
,dep
,pos
,fa
,a
,top
;
int tim,tot;
struct node
{
int l,r,sum,mx,mn,lazy;
}t
;
inline void add(int x,int y,int z)
{
go[++tot]=y;
next[tot]=head[x];
val[tot]=z;
head[x]=tot;
}
inline void dfs(int x)
{
size[x]=1;
for(int i=head[x];i;i=next[i])
{
int v=go[i];
if (v!=fa[x])
{
a[v]=val[i];
dep[v]=dep[x]+1;
fa[v]=x;
dfs(v);
size[x]+=size[v];
}
}
}
inline void dfs1(int x,int chain)
{
int k=0;
pos[x]=++tim;
top[x]=chain;
for(int i=head[x];i;i=next[i])
{
int v=go[i];
if (v!=fa[x])
{
if (size[v]>size[k])k=v;
}
}
if (!k)return;
son[x]=k;
dfs1(k,chain);
for(int i=head[x];i;i=next[i])
{
int v=go[i];
if (v!=fa[x]&&v!=son[x])
{
dfs1(v,v);
}
}
}
inline void build(int x,int l,int r)
{
t[x].l=l,t[x].r=r;
if (l==r)return;
int mid=(l+r)>>1;
build(x<<1,l,mid);
build(x<<1|1,mid+1,r);
}
void pushlazy(int d)
{
if (t[d].lazy==0||t[d].l==t[d].r) return;
t[d*2].lazy=1-t[d*2].lazy;
t[d*2+1].lazy=1-t[d*2+1].lazy;
t[d].lazy=0;
t[d*2].sum=-t[d*2].sum;
int w=t[d*2].mn;t[d*2].mn=-t[d*2].mx;t[d*2].mx=-w;
t[d*2+1].sum=-t[d*2+1].sum;
w=t[d*2+1].mn;t[d*2+1].mn=-t[d*2+1].mx;t[d*2+1].mx=-w;
}

void change(int d,int x,int y)
{
pushlazy(d);
if (t[d].l==t[d].r)
{
if (x==1)
{
t[d].mn=inf;
t[d].mx=-inf;
t[d].sum=0;
}else t[d].mn=t[d].mx=t[d].sum=y;
return;
}
int mid=(t[d].l+t[d].r)/2;
if (x<=mid) change(d*2,x,y);
else change(d*2+1,x,y);
t[d].mn=min(t[d*2].mn,t[d*2+1].mn);
t[d].mx=max(t[d*2].mx,t[d*2+1].mx);
t[d].sum=t[d*2].sum+t[d*2+1].sum;
}

void queryoppo(int d,int x,int y)
{
pushlazy(d);
if (t[d].l==x&&t[d].r==y)
{
t[d].sum=-t[d].sum;
int w=t[d].mn;t[d].mn=-t[d].mx;t[d].mx=-w;
t[d].lazy=1;
return;
}
int mid=(t[d].l+t[d].r)/2;
if (y<=mid) queryoppo(d*2,x,y);
else if (x>mid) queryoppo(d*2+1,x,y);
else
{
queryoppo(d*2,x,mid);
queryoppo(d*2+1,mid+1,y);
}
t[d].mn=min(t[d*2].mn,t[d*2+1].mn);
t[d].mx=max(t[d*2].mx,t[d*2+1].mx);
t[d].sum=t[d*2].sum+t[d*2+1].sum;
}

void solveoppo(int x,int y)
{
while (top[x]!=top[y])
{
if (dep[top[x]]<dep[top[y]]) swap(x,y);
queryoppo(1,pos[top[x]],pos[x]);
x=fa[top[x]];
}
if (x==y) return;
if (dep[x]>dep[y]) swap(x,y);
x=son[x];
queryoppo(1,pos[x],pos[y]);
}

int querysum(int d,int x,int y)
{
pushlazy(d);
if (t[d].l==x&&t[d].r==y) return t[d].sum;
int mid=(t[d].l+t[d].r)/2;
if (y<=mid) return querysum(d*2,x,y);
else if (x>mid) return querysum(d*2+1,x,y);
else return querysum(d*2,x,mid)+querysum(d*2+1,mid+1,y);
}

int solvesum(int x,int y)
{
int sum=0;
while (top[x]!=top[y])
{
if (dep[top[x]]<dep[top[y]]) swap(x,y);
sum+=querysum(1,pos[top[x]],pos[x]);
x=fa[top[x]];
}
if (x==y) return sum;
if (dep[x]>dep[y]) swap(x,y);
x=son[x];
sum+=querysum(1,pos[x],pos[y]);
return sum;
}

int querymin(int d,int x,int y)
{
pushlazy(d);
if (t[d].l==x&&t[d].r==y) return t[d].mn;
int mid=(t[d].l+t[d].r)/2;
if (y<=mid) return querymin(d*2,x,y);
else if (x>mid) return querymin(d*2+1,x,y);
else return min(querymin(d*2,x,mid),querymin(d*2+1,mid+1,y));
}

int solvemin(int x,int y)
{
int mn=inf;
while (top[x]!=top[y])
{
if (dep[top[x]]<dep[top[y]]) swap(x,y);
mn=min(mn,querymin(1,pos[top[x]],pos[x]));
x=fa[top[x]];
}
if (x==y) return mn;
if (dep[x]>dep[y]) swap(x,y);
x=son[x];
mn=min(mn,querymin(1,pos[x],pos[y]));
return mn;
}

int querymax(int d,int x,int y)
{
pushlazy(d);
if (t[d].l==x&&t[d].r==y) return t[d].mx;
int mid=(t[d].l+t[d].r)/2;
if (y<=mid) return querymax(d*2,x,y);
else if (x>mid) return querymax(d*2+1,x,y);
else return max(querymax(d*2,x,mid),querymax(d*2+1,mid+1,y));
}

int solvemax(int x,int y)
{
int mx=-inf;
while (top[x]!=top[y])
{
if (dep[top[x]]<dep[top[y]]) swap(x,y);
mx=max(querymax(1,pos[top[x]],pos[x]),mx);
x=fa[top[x]];
}
if (x==y) return mx;
if (dep[x]>dep[y]) swap(x,y);
x=son[x];
mx=max(mx,querymax(1,pos[x],pos[y]));
return mx;
}
int main()
{
scanf("%d",&n);
fo(i,1,n-1)
{
int x,y,z;
scanf("%d%d%d",&x,&y,&z);
x++,y++;
add(x,y,z);
add(y,x,z);
}
dfs(1);
dfs1(1,0);
build(1,1,n);
fo(i,1,n)change(1,pos[i],a[i]);
int q;
scanf("%d",&q);
fo(i,1,q)
{
char ch[10];
int x,y;
scanf("%s%d%d",ch,&x,&y);
if (ch[0]!='C')
{
x++,y++;
}
if (ch[0]=='C')
if(dep[go[x*2-1]]>dep[go[x*2]])change(1,pos[go[x*2-1]],y);
else change(1,pos[go[x*2]],y);
else if (ch[0]=='N')solveoppo(x,y);
else
{
if (ch[0]=='S')printf("%d\n",solvesum(x,y));
else if (ch[1]=='I')printf("%d\n",solvemin(x,y));
else printf("%d\n",solvemax(x,y));
}
}
}