BZOJ 2002: [Hnoi2010]Bounce 弹飞绵羊 (LCT维护深度)

要维护深度,就维护一下size就行了.access一下x,那么从根->x这一条链就独立成为一棵splay,那么splay的size节点数就是x的深度.

删边的时候直接access一下,splay一下,那么在原树中的父亲就是自己的右儿子,断掉那条边,再upd即可.

CODE

#include <cstdio>
#include <cstring>
#include <algorithm>
using namespace std;
typedef long long LL;
template<typename T>inline void read(T &num) {
	char ch; int flg = 1;
	while((ch=getchar())<'0'||ch>'9')if(ch=='-')flg=-flg;
	for(num=0;ch>='0'&&ch<='9';num=num*10+ch-'0',ch=getchar());
	num*=flg;
}
const int MAXN = 200005;
int n, q;
namespace LCT {
	#define ls ch[x][0]
	#define rs ch[x][1]
	int ch[MAXN][2], fa[MAXN], sz[MAXN];
	bool rev[MAXN];
	inline bool isr(int x) { return ch[fa[x]][0] != x && ch[fa[x]][1] != x; }
	inline bool get(int x) { return x == ch[fa[x]][1]; }
	inline void upd(int x) {
		sz[x] = sz[ls] + sz[rs] + 1;
	}
	inline void rot(int x) {
		int y = fa[x], z = fa[y], l = get(x), r = l^1;
		if(!isr(y)) ch[z][get(y)] = x;
		fa[ch[x][r]] = y; fa[y] = x; fa[x] = z;
		ch[y][l] = ch[x][r]; ch[x][r] = y;
		upd(y), upd(x);
	}
	inline void mt(int x) { if(rev[x]) rev[x] ^= 1, rev[ls] ^= 1, rev[rs] ^= 1, swap(ls, rs); }
	void mtpath(int x) { if(!isr(x)) mtpath(fa[x]); mt(x); }
	inline void splay(int x) {
		mtpath(x);
		for(; !isr(x); rot(x))
			if(!isr(fa[x])) rot(get(x)==get(fa[x])?fa[x]:x);
	}
	inline int access(int x) { int y=0;
		for(; x; x=fa[y=x]) splay(x), ch[x][1]=y, upd(x);
		return y;
	}
	inline void bert(int x) { access(x), splay(x), rev[x] ^= 1; }
	inline int sert(int x) {
		access(x), splay(x);
		for(; ch[x][0]; x=ch[x][0]);
		return x;
	}
	inline void link(int x, int y) {
		bert(x);
		if(sert(y) == x) return;
		fa[x] = y;
	}
	inline void cut(int x, int y) {
		bert(x), access(y), splay(y);
		if(sert(y) != x || fa[x] != y || ch[x][1] != 0) return;
		fa[x] = ch[y][0] = 0; upd(y);
	}
	inline void modify(int x, int val) {
		access(x), splay(x);
		ch[x][0] = fa[ch[x][0]] = 0; upd(x);
		if(x + val <= n) link(x, x+val);
	}
	inline int split(int x, int y) {
		bert(x), access(y), splay(y);
		return y;
	}
	inline int querysz(int x) {
		access(x), splay(x);
		return sz[x];
	}
}
using namespace LCT;
int main () {
	read(n);
	for(int i = 1, k; i <= n; ++i) {
		read(k);
		if(i+k <= n) link(i, i+k);
	}
	read(q);
	int opt, x, y;
	while(q--) {
		read(opt), read(x); ++x;
		if(opt == 1) printf("%d\n", querysz(x));
		else read(y), modify(x, y);
	}
}