[BZOJ2836]魔法树（链剖+dfs序）

题目描述

传送门

题解

链剖+dfs序裸题。
强转又搞错了？

代码

#include
#include
#include
using namespace std;
#define LL long long
const int max_n=1e5+5;
const int max_tree=max_n*4;
const int max_m=max_n;

LL n,m,x,y,q,u,t,d,N; LL ans;
LL tot,point[max_n],nxt[max_m],v[max_m];
LL size[max_n],h[max_n],father[max_n],top[max_n],in[max_n],out[max_n],son[max_n];
LL sum[max_tree],delta[max_tree];
char opt[20];

inline void addedge(LL x,LL y)
{
    ++tot; nxt[tot]=point[x]; point[x]=tot; v[tot]=y;
}
inline void dfs_1(LL x,LL fa,LL dep)
{
    size[x]=1; h[x]=dep; father[x]=fa;
    LL maxson=0;
    for (LL i=point[x];i;i=nxt[i])
        if (v[i]!=fa)
        {
            dfs_1(v[i],x,dep+1);
            size[x]+=size[v[i]];
            if (size[v[i]]>maxson)
            {
                maxson=size[v[i]];
                son[x]=v[i];
            }
        }
}
inline void dfs_2(LL x,LL fa)
{
    if (son[fa]!=x) top[x]=x;
    else top[x]=top[fa];
    in[x]=++N;
    if (son[x]) dfs_2(son[x],x);
    for (LL i=point[x];i;i=nxt[i])
        if (v[i]!=fa&&v[i]!=son[x])
            dfs_2(v[i],x);
    out[x]=N;
}
inline void update(LL now)
{
    sum[now]=sum[now<<1]+sum[now<<1|1];
}
inline void pushdown(LL now,LL l,LL r,LL mid)
{
    if (delta[now])
    {
        sum[now<<1]+=delta[now]*(LL)(mid-l+1);
        delta[now<<1]+=delta[now];
        sum[now<<1|1]+=delta[now]*(LL)(r-mid);
        delta[now<<1|1]+=delta[now];
        delta[now]=0;
    }
}
inline void interval_change(LL now,LL l,LL r,LL lrange,LL rrange,LL v)
{
    LL mid=(l+r)>>1;
    if (lrange<=l&&r<=rrange)
    {
        sum[now]+=v*(LL)(r-l+1);
        delta[now]+=v;
        return;
    }
    pushdown(now,l,r,mid);
    if (lrange<=mid) interval_change(now<<1,l,mid,lrange,rrange,v);
    if (mid+1<=rrange) interval_change(now<<1|1,mid+1,r,lrange,rrange,v);
    update(now);
}
inline LL query(LL now,LL l,LL r,LL lrange,LL rrange)
{
    LL mid=(l+r)>>1;LL ans=0;
    if (lrange<=l&&r<=rrange) return sum[now];
    pushdown(now,l,r,mid);
    if (lrange<=mid) ans+=query(now<<1,l,mid,lrange,rrange);
    if (mid+1<=rrange) ans+=query(now<<1|1,mid+1,r,lrange,rrange);
    return ans;
}
int main()
{
    scanf("%lld",&n);
    for (LL i=1;i"%lld%lld",&x,&y);
        x++; y++;
        addedge(x,y);
    }
    dfs_1(1,0,1);
    dfs_2(1,0);
    scanf("%lld",&q);
    for (LL i=1;i<=q;++i)
    {
        scanf("%s",opt);
        if (opt[0]=='A')
        {
            scanf("%lld%lld%lld",&u,&t,&d);
            ++u; ++t;
            LL f1=top[u],f2=top[t];
            while (f1!=f2)
            {
                if (h[f1]1,1,N,in[f1],in[u],d);
                u=father[f1];
                f1=top[u];
            }
            if (in[u]>in[t]) swap(u,t);
            interval_change(1,1,N,in[u],in[t],d);
        }
        else
        {
            scanf("%lld",&u);
            ++u;
            ans=query(1,1,N,in[u],out[u]);
            printf("%lld\n",ans);
        }
    }
}

手工栈

#include
#include
#include
using namespace std;
#define LL long long
const int max_n=1e5+5;
const int max_tree=max_n*4;
const int max_m=max_n;

LL n,m,x,y,q,u,t,d,N; LL ans;
LL tot,point[max_n],nxt[max_m],v[max_m];
LL size[max_n],h[max_n],father[max_n],top[max_n],in[max_n],out[max_n],son[max_n];
LL sum[max_tree],delta[max_tree];
char opt[20];
int stack[max_n],cur[max_n];bool use[max_n];

inline void addedge(LL x,LL y)
{
    ++tot; nxt[tot]=point[x]; point[x]=tot; v[tot]=y;
}
void dfs_1()
{
    int tmp=0;
    stack[++tmp]=1;h[1]=1;size[1]=1LL;
    for (int i=1;i<=n;++i) cur[i]=point[i];
    while (tmp)
    {
        int x=stack[tmp];
        if (cur[x]&&father[x]==v[cur[x]]) cur[x]=nxt[cur[x]];
        if (!cur[x])
        {
            --tmp;
            if (father[x])
            {
                size[father[x]]+=size[x];
                if (size[son[father[x]]]int vt=v[cur[x]];
        stack[++tmp]=vt;
        size[vt]=1LL;h[vt]=h[x]+1;father[vt]=x;
        cur[x]=nxt[cur[x]];
    }
}
void dfs_2()
{
    int tmp=0;
    stack[++tmp]=1;top[1]=1;in[1]=++N;
    for (int i=1;i<=n;++i) cur[i]=point[i];
    while (tmp)
    {
        int x=stack[tmp];
        if (!use[x])
        {
            use[x]=1;
            int vt=son[x];
            if (vt)
            {
                stack[++tmp]=vt;
                in[vt]=++N;
                top[vt]=top[x];
            }
            continue;
        }
        while (cur[x]&&(father[x]==v[cur[x]]||son[x]==v[cur[x]])) cur[x]=nxt[cur[x]];
        if (!cur[x])
        {
            int vt=stack[tmp--];
            out[vt]=N;
        }
        else
        {
            int vt=v[cur[x]];
            stack[++tmp]=vt;
            in[vt]=++N;
            top[vt]=vt;
            cur[x]=nxt[cur[x]];
        }
    }
}
inline void update(LL now)
{
    sum[now]=sum[now<<1]+sum[now<<1|1];
}
inline void pushdown(LL now,LL l,LL r,LL mid)
{
    if (delta[now])
    {
        sum[now<<1]+=delta[now]*(LL)(mid-l+1);
        delta[now<<1]+=delta[now];
        sum[now<<1|1]+=delta[now]*(LL)(r-mid);
        delta[now<<1|1]+=delta[now];
        delta[now]=0;
    }
}
inline void interval_change(LL now,LL l,LL r,LL lrange,LL rrange,LL v)
{
    LL mid=(l+r)>>1;
    if (lrange<=l&&r<=rrange)
    {
        sum[now]+=v*(LL)(r-l+1);
        delta[now]+=v;
        return;
    }
    pushdown(now,l,r,mid);
    if (lrange<=mid) interval_change(now<<1,l,mid,lrange,rrange,v);
    if (mid+1<=rrange) interval_change(now<<1|1,mid+1,r,lrange,rrange,v);
    update(now);
}
inline LL query(LL now,LL l,LL r,LL lrange,LL rrange)
{
    LL mid=(l+r)>>1;LL ans=0;
    if (lrange<=l&&r<=rrange) return sum[now];
    pushdown(now,l,r,mid);
    if (lrange<=mid) ans+=query(now<<1,l,mid,lrange,rrange);
    if (mid+1<=rrange) ans+=query(now<<1|1,mid+1,r,lrange,rrange);
    return ans;
}
int main()
{
    scanf("%lld",&n);
    for (LL i=1;i"%lld%lld",&x,&y);
        x++; y++;
        addedge(x,y);
    }
    dfs_1();
    dfs_2();
    scanf("%lld",&q);
    for (LL i=1;i<=q;++i)
    {
        scanf("%s",opt);
        if (opt[0]=='A')
        {
            scanf("%lld%lld%lld",&u,&t,&d);
            ++u; ++t;
            LL f1=top[u],f2=top[t];
            while (f1!=f2)
            {
                if (h[f1]1,1,N,in[f1],in[u],d);
                u=father[f1];
                f1=top[u];
            }
            if (in[u]>in[t]) swap(u,t);
            interval_change(1,1,N,in[u],in[t],d);
        }
        else
        {
            scanf("%lld",&u);
            ++u;
            ans=query(1,1,N,in[u],out[u]);
            printf("%lld\n",ans);
        }
    }
}