LuoguP3690 【模板】Link Cut Tree （LCT）

勉强算是结了个大坑吧或者才开始

#include <cstdio>
#include <iostream>
#include <cstring>
#include <algorithm>
#include <cmath>
#define R(a,b,c) for(register int a = (b); (a) <= (c); ++(a))
#define nR(a,b,c) for(register int a = (b); (a) >= (c); --(a))
#define Fill(a,b) memset(a, b, sizeof(a))
#define Swap(a,b) ((a) ^= (b) ^= (a) ^= (b))
#define ll long long
#define u32 unsigned int
#define u64 unsigned long long
 
#define ON_DEBUGG
 
#ifdef ON_DEBUGG
 
#define D_e_Line printf("\n----------\n")
#define D_e(x) cout << (#x) << " : " << x << endl
#define Pause() system("pause")
#define FileOpen() freopen("in.txt", "r", stdin)
#define FileSave() freopen("out.txt", "w", stdout)
#include <ctime>
#define TIME() fprintf(stderr, "\ntime: %.3fms\n", clock() * 1000.0 / CLOCKS_PER_SEC)

#else
 
#define D_e_Line ;
#define D_e(x) ;
#define Pause() ;
#define FileOpen() ;
#define FileSave() ;
#define TIME() ;
//char buf[1 << 21], *p1 = buf, *p2 = buf;
//#define getchar() (p1 == p2 && (p2 = (p1 = buf) + fread(buf, 1, 1 << 21, stdin), p1 == p2) ? EOF : *p1++)
 
#endif
 
using namespace std;
struct ios{
    template<typename ATP>inline ios& operator >> (ATP &x){
        x = 0; int f = 1; char ch;
        for(ch = getchar(); ch < '0' || ch > '9'; ch = getchar()) if(ch == '-') f = -1;
        while(ch >= '0' && ch <= '9') x = x * 10 + (ch ^ '0'), ch = getchar();
        x *= f;
        return *this;
    }
}io;
 
template<typename ATP>inline ATP Max(ATP a, ATP b){
    return a > b ? a : b;
}
template<typename ATP>inline ATP Min(ATP a, ATP b){
    return a < b ? a : b;
}
template<typename ATP>inline ATP Abs(ATP a){
    return a < 0 ? -a : a;
}

const int N = 300007;

struct node {
    int ch[2], fa, val, sum;
    bool rev;
}t[N];
#define ls t[u].ch[0]
#define rs t[u].ch[1]

inline bool Ident(int u) {
    return t[t[u].fa].ch[1] == u;
}

inline bool IsRoot(int u) {
    return t[t[u].fa].ch[0] != u && t[t[u].fa].ch[1] != u;
}

inline void Pushup(int u) {
    t[u].sum = t[u].val ^ t[ls].sum ^ t[rs].sum;
}

inline void Pushrev(int u) {
    Swap(t[u].ch[0], t[u].ch[1]);
    t[u].rev ^= 1;
}

inline void Pushdown(int u) {
    if(!t[u].rev) return;
    if(t[u].ch[0]) Pushrev(t[u].ch[0]);
    if(t[u].ch[1]) Pushrev(t[u].ch[1]);
    t[u].rev = 0;
}

int sta[N], top;

inline void Rotate(int x) {
	int y = t[x].fa, z = t[y].fa, k = Ident(x);
	t[x].fa = z; if(!IsRoot(y)) t[z].ch[Ident(y)] = x;
	t[y].ch[k] = t[x].ch[k ^ 1], t[t[x].ch[k ^ 1]].fa = y;
	t[x].ch[k ^ 1] = y, t[y].fa = x;
	Pushup(y), Pushup(x);
}

inline void Splay(int u) {
	int x = u;
    top = 0;
    while(!IsRoot(u)) {
    	sta[++top] = u;
    	u = t[u].fa;
	}
	sta[++top] = u;
	nR(i,top,1){
		Pushdown(sta[i]);
	}
    while(!IsRoot(x)) {
    	int y = t[x].fa;
    	if(!IsRoot(y)){
    		Ident(x) == Ident(y) ? Rotate(y) : Rotate(x); 
		}
		Rotate(x);
	}
	Pushup(x);
}

inline void Access(int u) {
    for(int v = 0; u; v = u, u = t[u].fa){
        Splay(u);
        t[u].ch[1] = v;
        Pushup(u);
    }
}

inline void MakeRoot(int u) {
    Access(u);
    Splay(u);
    Pushrev(u);
}

inline int FindRoot(int u) {
    Access(u);
    Splay(u);
    while(ls) u = ls;
    Splay(u);
    return u;
}

inline void Split(int u, int v) {
    MakeRoot(u);
    Access(v);
    Splay(v);
}

inline void Link(int u, int v) {
    Split(u, v);
    t[u].fa = v;
}

inline void Cut(int u, int v){
    MakeRoot(u);
    if(FindRoot(v) == u && t[v].fa == u && !t[v].ch[0]){
    	t[v].fa = t[u].ch[1] = 0;
    	Pushup(u);
	}
}

inline void Modify(int u, int w) {
//    Access(u);
    Splay(u);
    t[u].val = w;
    Pushup(u);
}

int main() {
//FileOpen();
//FileSave();
	int n, m;
	io >> n >> m;
    R(i,1,n){
    	io >> t[i].val;
    	t[i].sum = t[i].val;
	}
    while(m--){
    	int opt, x, y;
    	io >> opt >> x >> y;
        switch(opt){
	        case 0:
	            Split(x, y);
	            printf("%d\n", t[y].sum);
	            break;
	        case 1:
	            Link(x, y);
	            break;
	        case 2:
	            Cut(x, y);
	            break;
	        case 3:
	            Modify(x, y);
	            break;
	        }
    }
    return 0;
}