luoguP3920 [WC2014]紫荆花之恋 动态点分治 + 替罪羊树


意外的好写.....


考虑点分

\(dis(i, j) \leq r_i + r_j\)

对于过分治中心一点\(u\),有

\(dis(i, u) - r_i = dis(j, u) + r_j\)

对于同一子树内需要去重

原本是考虑用值域线段树来维护的,看了看\(10^9\)的范围,空间估计开不下

那就用平衡树吧...


用动态点分来维护答案,每次默认把\(i\)归到父亲的分治结构中

如果某个分治结构过于不平衡,那么就暴力重构

注意一下,一个点分治中的分治结构在树中对应一个联通块,没有任何其他的性质...

(我用\(n \log n\)的时间直接暴力维护了,感觉应该有更好的办法)

和二叉树的分析差不多,复杂度是\(O(n \log^2 n)\)的吧...


一开始受到了打树静态的动态点分治的影响

对于分治中心\(u\),直接把每个子树的信息存在了和\(u\)有对应连边的点上...

事实上,应该存在对应子树的重心上,重构的时候才不会出错...


#include <map>
#include <vector>
#include <cstdio>
#include <cstring>
#include <iostream>
#include <algorithm>
using namespace std;

#define ll long long
#define ri register int
#define rep(io, st, ed) for(ri io = st; io <= ed; io ++)
#define drep(io, ed, st) for(ri io = ed; io >= st; io --)

#define gc getchar
inline int read() {
    int p = 0, w = 1; char c = gc();
    while(c > '9' || c < '0') { if(c == '-') w = -1; c = gc(); }
    while(c >= '0' && c <= '9') p = p * 10 + c - '0', c = gc();
    return p * w;
}
    
const int sid = 3e5 + 5;
const int cid = 5e6 + 5;
    
struct stO_Mxl_Orz {
    
    int trash[cid], id, top;
    
    struct Yume_Alive_Forever {
        int sz, pri, num, son[2];
        ll val;
    } t[cid];
    
    inline int rand() {
        static int seed = 23333333;
        return seed = (seed * 97103LL) % 2147483647;
    }
    
    #define ls(o) t[(o)].son[0]
    #define rs(o) t[(o)].son[1]
    
    inline int newnode(ll v) {
        int ip = top ? trash[top --] : ++ id;
        ls(ip) = rs(ip) = 0; t[ip].sz = t[ip].num = 1;
        t[ip].val = v; t[ip].pri = rand();
        return ip;
    }
    
    inline void upd(int o) {
        t[o].sz = t[ls(o)].sz + t[rs(o)].sz + t[o].num;
    }
    
    inline void recycle(int &o) {
        if(!o) return;      
        recycle(ls(o)); recycle(rs(o));
        trash[++ top] = o;
    }
    
    inline void rotate(int &o, int p) {
        int u = t[o].son[p];
        t[o].son[p] = t[u].son[!p]; t[u].son[!p] = o;
        upd(o); upd(u); o = u;
    }
    
    inline void insert(int &o, ll v) {
        if(!o) { o = newnode(v); return; }
        t[o].sz ++;
        if(v == t[o].val) { t[o].num ++; return; }
        int nxt = v > t[o].val;
        insert(t[o].son[nxt], v);
        if(t[o].pri > t[t[o].son[nxt]].pri) rotate(o, nxt);
    }
    
    inline int qry(int o, ll v) {
        if(!o) return 0;
        if(v == t[o].val) return t[ls(o)].sz + t[o].num;
        if(v < t[o].val) return qry(ls(o), v);
        else return t[ls(o)].sz + t[o].num + qry(rs(o), v);
    }
    
} myk;

bool debug;

ll dit[sid];
int dep[sid], up[sid][17];
inline int lca(int u, int v) {
    if(dep[u] < dep[v]) swap(u, v);
    int d = dep[u] - dep[v];
    drep(i, 16, 0) if(d & (1 << i)) u = up[u][i];
    if(u == v) return u;
    drep(i, 16, 0) 
        if(up[u][i] != up[v][i]) u = up[u][i], v = up[v][i];
    if(u == v) return u;
    return up[u][0];
}

inline ll dis(int u, int v) {
    return dit[u] + dit[v] - (dit[lca(u, v)] << 1);
}

ll ans;
int r[sid], fa[sid];
int msx[sid], fd[sid], rt[sid], lrt[sid];

int asz, cnp, tim, hrt, ban;
int son[sid], sz[sid], ok[sid], vis[sid];
int cap[sid], nxt[sid], node[sid], len[sid]; 

inline void addedge(int u, int v, int w) {
    nxt[++ cnp] = cap[u]; cap[u] = cnp; node[cnp] = v; len[cnp] = w;
    nxt[++ cnp] = cap[v]; cap[v] = cnp; node[cnp] = u; len[cnp] = w;
}

#define cur node[i]
inline void grt(int o, int fa) {
    son[o] = 0; sz[o] = 1;
    for(int i = cap[o]; i; i = nxt[i])
    if(ok[cur] == tim && vis[cur] != tim  && cur != fa) {
        grt(cur, o); sz[o] += sz[cur];
        if(sz[cur] > son[o]) son[o] = sz[cur];
    }
    son[o] = max(son[o], asz - son[o]);
    if(son[o] < son[hrt]) hrt = o;
}

inline void dfs(int o, int fa) {
    sz[o] = 1;
    for(int i = cap[o]; i; i = nxt[i])
        if(ok[cur] == tim && vis[cur] != tim && cur != fa)
            dfs(cur, o), sz[o] += sz[cur];
}

vector <int> as[sid];
inline void dfs(int o, int fa, int anc1, int anc2, ll lev) {
    as[anc2].push_back(o);
    myk.insert(rt[anc2], lev - r[o]);
    myk.insert(lrt[anc1], lev - r[o]);
    for(int i = cap[o]; i; i = nxt[i])
        if(ok[cur] == tim && vis[cur] != tim && cur != fa)
            dfs(cur, o, anc1, anc2, lev + len[i]);
}

inline void solve(int o) {
    vis[o] = tim;
    as[o].push_back(o);
    myk.insert(rt[o], - r[o]);
    for(int i = cap[o]; i; i = nxt[i]) 
    if(ok[cur] == tim && vis[cur] != tim && cur != ban) dfs(cur, o);
    msx[o] = 0;
    for(int i = cap[o]; i; i = nxt[i]) 
    if(ok[cur] == tim && vis[cur] != tim) {
        msx[o] = max(msx[o], sz[cur]);
        asz = sz[cur]; hrt = 0; 
        grt(cur, o); fd[hrt] = o; 
        dfs(cur, o, hrt, o, len[i]);
        solve(hrt);
    }
}

inline void dfs(int o, int fa, int anc) {
    as[o].clear();
    myk.recycle(rt[o]); rt[o] = 0; 
    myk.recycle(lrt[o]); lrt[o] = 0;
    if(ban) myk.insert(lrt[anc], dis(o, ban) - r[o]);
    for(int i = cap[o]; i; i = nxt[i])
        if(ok[cur] == tim && cur != ban && cur != fa) 
            dfs(cur, o, anc);
}

inline void rebuild(int o) {
    ++ tim; ban = fd[o]; 
    asz = myk.t[rt[o]].sz; hrt = 0;
    for(auto x : as[o]) ok[x] = tim; 
    grt(o, ban); 
    dfs(hrt, ban, hrt);
    fd[hrt] = ban;
    solve(hrt); 
}

inline void modify(int o) {
    fd[o] = fa[o];
    for(ri now = fd[o], lst = o; now; lst = now, now = fd[now]) {   
        ll v = dis(now, o);
        as[now].push_back(o);
        myk.insert(rt[now], v - r[o]);
        myk.insert(lrt[lst], v - r[o]);
        ans += myk.qry(rt[now], r[o] - v) - myk.qry(lrt[lst], r[o] - v);
        msx[now] = max(msx[now], myk.t[lrt[lst]].sz);
    }
    
    const double Yume_Saiko = 0.756412;
        
    int tmp = -1;
    for(ri now = fd[o]; now; now = fd[now])
        if(msx[now] >= myk.t[rt[now]].sz * Yume_Saiko) tmp = now;
    if(tmp != -1) rebuild(tmp);
}

const int mod = 1e9;
int main() {
    int Wahaha = read();
    int n = read(); son[0] = n + 1;
    for(ri i = 1; i <= n; i ++) {
        fa[i] = read() ^ (ans % mod);
        int c = read(); r[i] = read();
        
        addedge(fa[i], i, c);
        up[i][0] = fa[i];
        dep[i] = dep[fa[i]] + 1;
        dit[i] = dit[fa[i]] + c;
        for(ri j = 1; j <= 16; j ++)
            up[i][j] = up[up[i][j - 1]][j - 1];
         
        as[i].push_back(i);
        myk.insert(rt[i], -r[i]);
        if(i != 1) modify(i);
        printf("%lld\n", ans);
    }
    return 0;
}

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转载自www.cnblogs.com/reverymoon/p/10216291.html