[BZOJ 3123]森林

这题和 COT1 一定有 JQ 喵~

线段树的启发式合并，每次要连接两个点时就对比较小的那棵树暴力 DFS 一边

然后均摊时间依旧是 logn 的，均摊真是世界上最邪恶的东西了……

然后这题的数据是要卖萌么？！
testcase 的存在意义是被阿卡林噎掉了么？！

#include <cstdio>
#include <cstring>
#include <algorithm>
const int sizeOfPoint=100001;
const int sizeOfEdge=200002;
const int sizeOfNode=20000002;

inline int lg(int);
inline void swap(int & , int & );
inline char getch();
inline int getint();
inline void putint(int);

struct edge {int point; edge * next;};
edge memory_edge[sizeOfEdge], * port_edge=memory_edge;
inline edge * newedge(int, edge * );
inline void link(int, int);

struct node {int c; node * l , * r; inline node();};
node * null=new node();
node memory_node[sizeOfNode], * port_node=memory_node;
inline node * newnode(node * =null);
node * insert(node * , int, int, int);

int b[sizeOfPoint], s[sizeOfPoint];
int find(int);
inline void merge(int, int);

int testcase;
int N, M, T, U;
int p[sizeOfPoint], q[sizeOfPoint];
int f[sizeOfPoint], d[sizeOfPoint], a[32][sizeOfPoint];
edge * e[sizeOfPoint];
node * t[sizeOfPoint];
inline void clear();
inline bool cmp(int, int);
inline void discretization();
void dfs(int);
inline int lca(int, int);
inline int query(int, int, int);

int main()
{
    int lastans=0;

    testcase=getint();
    for (testcase=1;testcase;testcase--)
    {
        N=getint(), M=getint(), T=getint();
        clear();
        for (int i=1;i<=N;i++)
            p[i]=getint();
        for (int i=1;i<=M;i++)
        {
            int u=getint(), v=getint();
            link(u, v);
        }
        discretization();

        for (int i=1;i<=N;i++) if (f[i]==-1)
        {
            f[i]=0; d[i]=0;
            dfs(i);
        }

        for (int i=1;i<=T;i++)
        {
            char c=getch(); int x=getint()^lastans, y=getint()^lastans;
            if (c=='Q')
            {
                int k=getint()^lastans;
                lastans=query(x, y, k);
                putint(lastans);
            }
            else
            {
                int bx=find(x), by=find(y);
                if (bx==by) continue;
                if (s[bx]<s[by]) swap(x, y);
                link(x, y);
                f[y]=x; d[y]=d[x]+1;
                dfs(y);
            }
        }
    }

    return 0;
}

inline int lg(int x)
{
    return 31-__builtin_clz(x);
}
inline void swap(int & x, int & y)
{
    int z=x;
        x=y;
        y=z;
}
inline char getch()
{
    register char ch;
    do ch=getchar(); while (ch!='L' && ch!='Q');
    return ch;
}
inline int getint()
{
    register int num=0;
    register char ch=0, last;
    do last=ch, ch=getchar(); while (ch<'0' || ch>'9');
    do num=num*10+ch-'0', ch=getchar(); while (ch>='0' && ch<='9');
    if (last=='-') num=-num;
    return num;
}
inline void putint(int num)
{
    char stack[11];
    register int top=0;
    if (num==0) stack[top=1]='0';
    if (num<0) putchar('-'), num=-num;
    for ( ;num;num/=10) stack[++top]=num%10+'0';
    for ( ;top;top--) putchar(stack[top]);
    putchar('
');
}

inline edge * newedge(int point, edge * next)
{
    edge * ret=port_edge++;
    ret->point=point; ret->next=next;
    return ret;
}
inline void link(int u, int v)
{
    e[u]=newedge(v, e[u]);
    e[v]=newedge(u, e[v]);
    merge(u, v);
}

inline node::node()
{
    this->c=0;
    this->l=this;
    this->r=this;
}
inline node * newnode(node * t)
{
    node * newt=port_node++;
    *newt=*t;
    return newt;
}
node * insert(node * t, int l, int r, int k)
{
    t=newnode(t);
    t->c++;
    if (l==r) return t;

    int m=(l+r)>>1;
    if (k<=m) t->l=insert(t->l, l, m, k);
    else t->r=insert(t->r, m+1, r, k);
    return t;
}

int find(int u)
{
    return !b[u]?u:b[u]=find(b[u]);
}
inline void merge(int u, int v)
{
    u=find(u); v=find(v);
    b[v]=u; s[u]+=s[v];
}

inline void clear()
{
    port_edge=memory_edge;
    memset(e, 0, sizeof(e));
    port_node=memory_node;
    for (int i=0;i<=N;i++) t[i]=null;
    memset(f, -1, sizeof(f));
    memset(d, -1, sizeof(d));
    memset(b, 0, sizeof(b));
    memset(a, 0, sizeof(a));
    for (int i=1;i<=N;i++) s[i]=1;
}
inline bool cmp(int a, int b)
{
    return p[a]<p[b];
}
inline void discretization()
{
    static int k[sizeOfPoint];

    for (int i=1;i<=N;i++) k[i]=i;
    std::sort(k+1, k+N+1, cmp);

    q[U=1]=p[k[1]]; p[k[1]]=1;
    for (int i=2;i<=N;i++)
    {
        if (p[k[i]]>q[U]) q[++U]=p[k[i]];
        p[k[i]]=U;
    }
}
void dfs(int u)
{
    t[u]=insert(t[f[u]], 1, U, p[u]);
    if (d[u]>0)
    {
        int lim=lg(d[u]);
        a[0][u]=f[u];
        for (int i=1;i<=lim;i++)
            a[i][u]=a[i-1][a[i-1][u]];
        for (int i=lim+1;i<31;i++)
            a[i][u]=0;
    }

    for (edge * i=e[u];i;i=i->next) if (i->point!=f[u])
    {
        f[i->point]=u;
        d[i->point]=d[u]+1;
        dfs(i->point);
    }
}
inline int lca(int u, int v)
{
    if (d[u]<d[v]) swap(u, v);
    while (int dist=d[u]-d[v]) u=a[__builtin_ctz(dist)][u];
    if (u==v) return u;
    for (int i=31;i>=0;i--)
        if (a[i][u]!=a[i][v])
            u=a[i][u],
            v=a[i][v];
    return f[u];
}
inline int query(int a, int b, int k)
{
    int c=lca(a, b), d=f[c];
    node * ta=t[a], * tb=t[b], * tc=t[c], * td=t[d];
    int l=1, r=U, m;

    for ( ;l<r; )
    {
        m=(l+r)>>1;
        if (ta->l->c+tb->l->c-tc->l->c-td->l->c>=k)
        {
            ta=ta->l; tb=tb->l; tc=tc->l; td=td->l;
            r=m;
        }
        else
        {
            k-=ta->l->c+tb->l->c-tc->l->c-td->l->c;
            ta=ta->r; tb=tb->r; tc=tc->r; td=td->r;
            l=m+1;
        }
    }

    return q[l];
}