BZOJ 1036 [ZJOI2008]树的统计Count 树链剖分练手题

写过的第一道树剖题。之前看过几个课件，也没写过，这次直接YY出来的竟然能A。维护区间信息时没用线段树，用的Splay，只为练练手，然而就导致代码无下限的长，可是心酸。还好这次写了之后1A(233，明明输出优化没加负号Wa一次的)，不然还真不敢调。

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

struct node
{
int va, fa, lc, rc, sz, su, mx;
void set0()
{va=fa=lc=rc=sz=su=0; mx=-999999;}
};

struct SplayTree
{
node P[30005]; int root, cnt;

void maintain (int rt)
{
P[0].set0();
int lc = P[rt].lc, rc = P[rt].rc;
P[rt].sz = 1+P[lc].sz+P[rc].sz;
P[rt].su = P[rt].va+P[lc].su+P[rc].su;
P[rt].mx = max(P[rt].va, max(P[lc].mx,P[rc].mx));
}
void rotate (int rt)
{
int fa = P[rt].fa, gfa = P[fa].fa;
if (!gfa) root = rt;
if (P[fa].lc == rt)
{
P[fa].lc = P[rt].rc, P[rt].rc = fa;
P[P[fa].lc].fa = fa, P[fa].fa = rt;
}
else
{
P[fa].rc = P[rt].lc, P[rt].lc = fa;
P[P[fa].rc].fa = fa, P[fa].fa = rt;
}
if (P[gfa].lc == fa) P[gfa].lc = rt;
else P[gfa].rc = rt; P[rt].fa = gfa;
maintain(fa); maintain(rt);
}
int find (int rt, int k)
{
int rk = P[P[rt].lc].sz + 1;
if (rk == k) return rt;
if (rk > k) return find (P[rt].lc, k);
if (rk < k) return find (P[rt].rc, k-rk);
}
void splay (int rt)
{
while (rt != root)
{
int fa = P[rt].fa, gfa = P[fa].fa;
if (gfa&&((P[fa].lc==rt)==(P[gfa].lc==fa))) rotate(fa);
rotate (rt);
}
}
int split (int rt, int op)
{
splay (rt);
int res = op ? P[root].lc : P[root].rc;
if (op) P[root].lc = 0; else P[root].rc = 0;
P[res].fa = 0;
maintain(root);
return res;
}
void merge (int L, int R)
{
if (!L) {root=R; return;}
if (!R) {root=L; return;}
root = L;
splay (find(root,P[root].sz));
P[root].rc = R, P[R].fa = root;
maintain(root);
}

void insert (int va)
{
if (!root)
{
root = ++cnt;
P[1].va = P[1].mx = P[1].su = va;
P[1].sz = 1;
return ;
}
splay(P[root].sz);
P[root].rc = ++cnt;
P[cnt].va = P[cnt].mx = P[cnt].su = va;
P[cnt].sz = 1, P[cnt].fa = root;
maintain(root);
}
void update (int pos, int c)
{
int rt = find (root, pos);
splay (rt);
P[rt].va = c;
maintain(rt);
}
int qmax (int pl, int pr)
{
if (pl == 1)
{
int t = pr==P[root].sz ? pr : pr+1;
int rt = find (root, t);
splay (rt);
return t==pr ? P[root].mx : P[P[root].lc].mx;
}
int rtl = find (root, pl), rtr = find (root, pr);
int op1 = split(rtl, 1), op2 = split(rtr, 0);
int res = P[root].mx;
merge (root, op2);
merge (op1, root);
return res;
}
int qsum (int pl, int pr)
{
if (pl == 1)
{
int t = pr==P[root].sz ? pr : pr+1;
int rt = find (root, t);
splay (rt);
return t==pr ? P[root].su : P[P[root].lc].su;
}
int rtl = find (root, pl), rtr = find (root, pr);
int op1 = split(rtl, 1), op2 = split(rtr, 0);
int res = P[root].su;
merge (root, op2);
merge (op1, root);
return res;
}
}Solve;

void get (int &x)
{
char c = getchar(); bool neg = 0; x = 0;
while (c < '0' || c > '9')
{if (c == '-') neg = 1; c = getchar();}
while (c <= '9' && c >= '0') x = x*10+c-48, c = getchar();
if (neg) x = -x;
}
void put (int x)
{
char s[15]; int num = 0;
if (x < 0) {x = -x; putchar ('-');}
if (x == 0) putchar ('0');
while (x) s[++num] = (x%10)+48, x /= 10;
while (num) putchar (s[num--]);
putchar ('\n');
}
void get (char *s)
{
char c = getchar(); int num = 0;
while (c < 'A' || c > 'Z') c = getchar();
while ((c <= 'Z' && c >= 'A') || c == '-') s[num++] = c, c = getchar();
}

int n, q, e, cnt, h[30005], nx[60005], to[60005];
int val[30005], fa[30005], son[30005], head[30005], size[30005], Lsize[30005], deep[30005], belong[30005];
vector <int> clude[30005];

void Dfs1 (int rt, int f)
{
fa[rt] = f;
size[rt] = 1;
deep[rt] = deep[f] + 1;
for (int i = h[rt]; i; i = nx[i])
if (f != to[i]){
Dfs1(to[i],rt);
size[rt] += size[to[i]];
if (size[to[i]] > size[son[rt]]) son[rt] = to[i];
}
}
void Dfs2 (int rt, int f)
{
if (son[f] == rt) belong[rt] = belong[f], head[rt] = head[f];
else belong[rt] = ++cnt, head[rt] = rt;
clude[belong[rt]].push_back(rt);
Lsize[belong[rt]]++;
for (int i = h[rt]; i; i = nx[i])
if (f != to[i]) Dfs2(to[i], rt);
}

void Initialize()
{
get(n);
for (int i = 1; i < n; i++)
{
int a, b; get(a); get(b);
nx[++e] = h[a], h[a] = e, to[e] = b;
nx[++e] = h[b], h[b] = e, to[e] = a;
}
for (int i = 1; i <= n; i++) get(val[i]);

Dfs1(1, 0);
Dfs2(1, 0);
for (int i = 1; i <= cnt; i++)
{
Lsize[i] += Lsize[i-1];
for (int j = 0; j < clude[i].size(); j++) Solve.insert(val[clude[i][j]]);
}
}

int id (int t)
{
return deep[t]-deep[head[t]]+1+Lsize[belong[t]-1];
}

void Change (int rt, int c)
{
val[rt] = c;
Solve.update(id(rt), c);
}
void Getmax (int l, int r)
{
int res = -999999;
while (belong[l] != belong[r])
{
if (deep[head[l]] < deep[head[r]])
{
res = max (res, Solve.qmax(id(head[r]), id(r)));
r = fa[head[r]];
}
else
{
res = max (res, Solve.qmax(id(head[l]), id(l)));
l = fa[head[l]];
}
}
l = id(l), r = id(r);
if (r < l) swap (l, r);
res = max (res, Solve.qmax(l,r));
put (res);
}
void Getsum (int l, int r)
{
int res = 0;
while (belong[l] != belong[r])
{
if (deep[head[l]] < deep[head[r]])
{
res += Solve.qsum(id(head[r]), id(r));
r = fa[head[r]];
}
else
{
res += Solve.qsum(id(head[l]), id(l));
l = fa[head[l]];
}
}
l = id(l), r = id(r);
if (r < l) swap (l, r);
res += Solve.qsum(l,r);
put (res);
}

void Work()
{
get(q);
while (q--)
{
char s[10]; get(s);
int a, b; get(a); get(b);
if (s[1] == 'H') Change(a, b);
if (s[1] == 'M') Getmax(a, b);
if (s[1] == 'S') Getsum(a, b);
}
}

int main ()
{
Initialize();
Work();
return 0;
}