bzoj1036树的统计Count

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单点修改，询问链最大，链和，LCT和树链剖分都可以写，不过LCT就是慢....

LCT：

#include<cstdio>#include<cstring>#include<algorithm>using namespace std;const int maxn=30010;int n,m,u[maxn],v[maxn];char s[7];struct LCT{int val[maxn],fa[maxn],c[maxn][2],sum[maxn],maxs[maxn],rev[maxn];bool isroot(int x){return (c[fa[x]][0]!=x)&&(c[fa[x]][1]!=x);}void flip(int x){swap(c[x][0],c[x][1]),rev[x]^=1;}void update(int x){int ls=c[x][0],rs=c[x][1];sum[x]=maxs[x]=val[x];if (ls) sum[x]+=sum[ls],maxs[x]=max(maxs[x],maxs[ls]);if (rs) sum[x]+=sum[rs],maxs[x]=max(maxs[x],maxs[rs]);}void down(int x){if (rev[x]) flip(c[x][0]),flip(c[x][1]),rev[x]^=1;}void relax(int x){if (!isroot(x)) relax(fa[x]);down(x);}int which(int x){return c[fa[x]][1]==x;}void rotate(int x){int y=fa[x],z=fa[y],nx=which(x),ny=which(y);fa[c[x][!nx]]=y,c[y][nx]=c[x][!nx];fa[x]=z;if (!isroot(y)) c[z][ny]=x;fa[y]=x,c[x][!nx]=y;update(y);}void splay(int x){relax(x);while (!isroot(x)){if (isroot(fa[x])) rotate(x);else if (which(x)==which(fa[x])) rotate(fa[x]),rotate(x);else rotate(x),rotate(x);}update(x);}void access(int x){for (int p=0;x;x=fa[x]) splay(x),fa[c[x][1]=p]=x,update(x),p=x;}void makeroot(int x){access(x),splay(x),flip(x),update(x);}void modify(int x,int v){val[x]=v,splay(x);}void link(int a,int b){makeroot(a),fa[a]=b;}void qmax(int a,int b){makeroot(a),access(b),splay(b),printf("%d\n",maxs[b]);}void qsum(int a,int b){makeroot(a),access(b),splay(b),printf("%d\n",sum[b]);}}T;int main(){scanf("%d",&n);for (int i=1;i<n;i++) scanf("%d%d",&u[i],&v[i]);for (int i=1,a;i<=n;i++) scanf("%d",&a),T.modify(i,a);for (int i=1;i<n;i++) T.link(u[i],v[i]);scanf("%d",&m);for (int i=1,a,b;i<=m;i++){scanf("%s%d%d",s,&a,&b);if (s[0]=='C') T.modify(a,b);else if (s[1]=='S') T.qsum(a,b);else T.qmax(a,b);}return 0;}

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