SPOJ 375 Query on a tree 树链剖分模板

第一次写树剖~


#include<iostream>
#include<cstring>
#include<cstdio>
#define L(u) u<<1
#define R(u) u<<1|1
using namespace std;
const int MAX=10005;
int t,head[MAX*2],next1[MAX*2],tov[MAX*2],val[MAX*2],tot,n;
int fa[MAX],w[MAX],son[MAX],depth[MAX],tot2,size[MAX];
int d[MAX][5],tree[MAX*4],top[MAX];
char ch[10];
inline void swap(int &a,int &b)
{
    int t;
    t=a;
    a=b;
    b=t;
} 
inline void add(int a,int b,int c)
{
    tot++;
    next1[tot]=head[a];
    head[a]=tot;
    tov[tot]=b;
    val[tot]=c;
}
inline void dfs1(int k)
{
    son[k]=0;
    size[k]=1;
    for (int i=head[k];i;i=next1[i])
     {
        int v=tov[i];
        if (v!=fa[k])
        {
            fa[v]=k;
            depth[v]=depth[k]+1;
            dfs1(v);
            son[k]=size[v]<size[son[k]]?son[k]:v;
            size[k]+=size[v];
        }
     }
}
inline void dfs2(int k,int _top)
{
    w[k]=++tot2;
    top[k]=_top;
    if (son[k]!=0) dfs2(son[k],_top);//the same _top
    for (int i=head[k];i;i=next1[i])
    {
        int v=tov[i];
        if (v!=fa[k]&&v!=son[k])
           dfs2(v,v);//the new _top;
    } 
}
inline void update(int u,int l,int r,int loc,int _value)
{
    if (l==loc&&r==loc)
    {
        tree[u]=_value;
        return ;
    }
    int mid=(l+r)>>1;
    if (loc<=mid) update(L(u),l,mid,loc,_value);
    else update(R(u),mid+1,r,loc,_value);
    tree[u]=max(tree[R(u)],tree[L(u)]);//pushup
}
void doit()
{
    memset(head,0,sizeof(head));
    memset(depth,0,sizeof(depth));
    memset(fa,0,sizeof(fa));
    memset(tree,0,sizeof(tree));
    tot2=tot=0;
    scanf("%d",&n);
    for (int i=1;i<=n-1;i++)
     {
        scanf("%d%d%d",&d[i][0],&d[i][1],&d[i][2]);
        add(d[i][0],d[i][1],d[i][2]);
        add(d[i][1],d[i][0],d[i][2]);
     }
     dfs1(1);
     dfs2(1,1);
     for (int i=1;i<=n-1;i++)
      {
           if (depth[d[i][0]]>depth[d[i][1]]) swap(d[i][0],d[i][1]);//make the higher depth node to map the Edge
         update(1,1,tot2,w[d[i][1]],d[i][2]); //change the value of the loc->w[d[i][1]]
      }
}
inline int query(int u,int l,int r,int l1,int r1)
{
    if (l1<=l&&r1>=r) return tree[u];
    int mid=(l+r)>>1;
    if (r1<=mid) return query(L(u),l,mid,l1,r1);
    else if (l1>mid) return query(R(u),mid+1,r,l1,r1);
    else {
        return max(query(L(u),l,mid,l1,r1),query(R(u),mid+1,r,l1,r1));
    }
}
int findans(int va,int vb)
{
    int f1,f2,ans;
    f1=top[va];
    f2=top[vb];
    ans=0;
    while (f1!=f2)//find lca
    {
        if (depth[f1]<depth[f2])
        {
            swap(f1,f2);
            swap(va,vb);
        }
        ans=max(ans,query(1,1,tot2,w[f1],w[va]));//swap make w[f1]<w[f2]
        if (f1==f2) return ans;//in the same chain
        va=fa[f1];f1=top[va];
    }
    if (va==vb) return ans;
    if (depth[va]>depth[vb]) swap(va,vb);
    return max(ans,query(1,1,tot2,w[son[va]],w[vb]));//the last do the f1=top[va]
}
void read()
{
    ch[0]='G';
    scanf("%s",ch);
}
void work()
{
    for (read();ch[0]!='D';read())
    {
        int x,y;
        scanf("%d%d",&x,&y);
        if (ch[0]=='Q') printf("%d
",findans(x,y));
        else update(1,1,tot2,w[d[x][1]],y);
    }
}
int main()
{
    scanf("%d",&t);
    for (int i=1;i<=t;i++)
     {
        doit();
        work();
     }
}