bzoj 2243: [SDOI2011]染色

 #include<cstdio>
 #include<iostream>
 #define M 1000006
 #define N 1000006
 using namespace std;
 int head[N],next[M],u[M],se[N],se1[N],n,m,size[N],l[N],lc[N][],f1[N],cnt,dui[N],lian[N],tim,l1,l2;
 int r1;
 struct data
 {
     int l,r,sum,tag;
 }shu[*N];
 void jia(int a1,int a2)
 {
     cnt++;
     next[cnt]=head[a1];
     head[a1]=cnt;
     u[cnt]=a2;
     return;
 }
 void dfs(int a1)
 {
     f1[a1]=;
     size[a1]=;
     for(int i=;i<=;i++)
       {
         if(l[a1]<(>>i))
           break;
         lc[a1][i]=lc[lc[a1][i-]][i-];
       }
     for(int i=head[a1];i;i=next[i])
       if(!f1[u[i]])
         {
             lc[u[i]][]=a1;
             l[u[i]]=l[a1]+;
             dfs(u[i]);
             size[a1]+=size[u[i]];
         }
     return;
 }
 void dfs1(int a1,int a2)
 {
     tim++;
     dui[a1]=tim;
     lian[a1]=a2;
     int k=;
     for(int i=head[a1];i;i=next[i])
       if(!dui[u[i]]&&size[k]<size[u[i]])
         k=u[i];
     if(!k)
       return;
     dfs1(k,a2);
     for(int i=head[a1];i;i=next[i])
       if(!dui[u[i]])
         dfs1(u[i],u[i]);
     return;
 }
 void geng(int a1)
 {
     shu[a1].l=shu[a1*].l;
     shu[a1].r=shu[a1*+].r;
     shu[a1].sum=shu[a1*].sum+shu[a1*+].sum;
     if(shu[a1*].r==shu[a1*+].l)
       shu[a1].sum--;
     return;
 }
 void build(int a1,int a2,int a3)
 {
     if(a2==a3)
       {
         shu[a1].sum=;
         shu[a1].l=se1[a2];
         shu[a1].r=se1[a2];
         return;
       }
     int mid=(a2+a3)>>;
     build(a1*,a2,mid);
     build(a1*+,mid+,a3);
     geng(a1);
     return;
 }
 int lca(int a1,int a2)
 {
     if(l[a1]<l[a2])
       swap(a1,a2);
     int a3=l[a1]-l[a2];
     for(int i=;i<=;i++)
       if(a3&(<<i))
         a1=lc[a1][i];
     for(int i=;i>=;i--)
       if(lc[a1][i]!=lc[a2][i])
         {
             a1=lc[a1][i];
             a2=lc[a2][i];
         }
     if(a1==a2)
       return a1;
     return lc[a1][];
 }
 void geng1(int a1)
 {
     int a2=shu[a1].l;
     shu[a1*].l=a2;
     shu[a1*].r=a2;
     shu[a1*].sum=;
     shu[a1*].tag=;
     shu[a1*+].l=a2;
     shu[a1*+].r=a2;
     shu[a1*+].sum=;
     shu[a1*+].tag=;
     shu[a1].tag=;
 }
 void gai1(int a1,int a2,int a3,int a4,int a5,int a6)
 {
     if(a4<=a2&&a5>=a3)
       {
          shu[a1].l=a6;
          shu[a1].r=a6;
          shu[a1].sum=;
          shu[a1].tag=;
          return;
       }
     if(shu[a1].tag)
       geng1(a1);
     int mid=(a2+a3)>>;
     if(a4<=mid)
       gai1(a1*,a2,mid,a4,a5,a6);
     if(a5>mid)
       gai1(a1*+,mid+,a3,a4,a5,a6);
     geng(a1);
 }
 void gai(int a1,int t,int a3)
 {
     for(;lian[a1]!=lian[t];)
       {
         gai1(,,n,dui[lian[a1]],dui[a1],a3);
         a1=lc[lian[a1]][];
       }
     gai1(,,n,dui[t],dui[a1],a3);
 }
 int xun1(int a1,int a2,int a3,int a4,int a5)
 {
     int ss=;
     if(a4<=a2&&a5>=a3)
       {
         if(l1==-)
           l1=shu[a1].l;
         r1=shu[a1].r;
         return shu[a1].sum;
       }
     if(shu[a1].tag)
       geng1(a1);
     int mid=(a2+a3)>>;
     if(a4<=mid)
       ss+=xun1(a1*,a2,mid,a4,a5);
     if(a5>mid)
       ss+=xun1(a1*+,mid+,a3,a4,a5);
     if(a4<=mid&&a5>mid&&shu[a1*].r==shu[a1*+].l)
       ss--;
     return ss;
 }
 int xun(int a1,int t)
 {
     int sum=;
     l2=-;
     for(;lian[a1]!=lian[t];)
       {
         l1=-;
         sum+=xun1(,,n,dui[lian[a1]],dui[a1]);
         a1=lc[lian[a1]][];
         if(r1==l2)
           sum--;
         l2=l1;
       }
     l1=-;
     sum+=xun1(,,n,dui[t],dui[a1]);
     if(r1==l2)
       sum--;
     return sum;
 }
 int main()
 {
     scanf("%d%d",&n,&m);
     for(int i=;i<=n;i++)
       scanf("%d",&se[i]);
     for(int i=;i<n;i++)
       {
         int a1,a2;
         scanf("%d%d",&a1,&a2);
         jia(a1,a2);
         jia(a2,a1);
       }
     dfs();
     dfs1(,);
     for(int i=;i<=n;i++)
       se1[dui[i]]=se[i];
     build(,,n);
     char ch[];
     for(int i=;i<=m;i++)
       {
         int a1,a2,a3=,a5=;
         scanf("%s%d%d",ch,&a1,&a2);
         int t=lca(a1,a2);
         if(ch[]=='C')
           {
             scanf("%d",&a3);
             gai(a1,t,a3);
             gai(a2,t,a3);
           }
         else
           {
             a3=xun(a1,t);
             a5=xun(a2,t);
             a3+=a5;
             a3--;
             printf("%d\n",a3);
           }
       }
     return ;
 }

一个树链剖分，怎么这么长~~~~(>_<)~~~~