快改的和题解一样了，但是就是 WA/ll

#include<bits/stdc++.h>
using namespace std;
struct Splay{
	stack<int> stk;
	int rt, tot, fa[300005], ch[300005][2], sum[300005], vl[300005], cnt[300005], sz[300005];
	bool r[300005];
	void pup(int u){
		sum[u] = sum[ch[u][0]] ^ sum[ch[u][1]] ^ vl[u];
	}
	bool isr(int u){
		return u == ch[fa[u]][1];
	}
	bool unr(int u){
		return (ch[fa[u]][0] == u || ch[fa[u]][1] == u);
	}
	void rev(int u){
		swap(ch[u][0], ch[u][1]);
		r[u] ^= 1;
	}
	void pdn(int u){
		if (r[u]){
			if (ch[u][0])
				rev(ch[u][0]);
			if (ch[u][1])
				rev(ch[u][1]);
			r[u] = 0;
		}
	}
	void rtt(int u){
		int v = fa[u], w = fa[v], op = isr(u);
		if (unr(v))
			ch[w][isr(v)] = u;
		ch[u][op ^ 1] = v;
		ch[v][op] = ch[u][op ^ 1];
		if (ch[u][op ^ 1])
			fa[ch[u][op ^ 1]] = v;
		fa[v] = u;
		fa[u] = w;
		pup(v);
	//	pup(u);
	}
	void splay(int u){
		int v = u, w;
		stk.push(v);
		while (unr(v)){
			v = fa[v];
			stk.push(v);
		}
		while (!stk.empty()){
			pdn(stk.top());
			stk.pop();
		}
		while (unr(u)){
			v = fa[u];
			if (unr(v)){
				if (isr(u) ^ isr(v))
					rtt(u);
				else
					rtt(v);
			}
			rtt(u);
		}
		pup(u);
	}
	void access(int u){
		for (int v = 0; u; v = u, u = fa[u]){
			splay(u);
			ch[u][1] = v;
			pup(u);
		}
	}
	void mkrt(int u){
		access(u);
		splay(u);
		rev(u);
	}
	int qrt(int u){
		access(u);
		splay(u);
		while (ch[u][0]){
			pdn(u);
			u = ch[u][0];
		}
		splay(u);
		return u;
	}
	void split(int u, int v){
		mkrt(u);
		access(v);
		splay(v);	
	}
	void link(int u, int v){
		mkrt(u);
		if (qrt(v) != u)
			fa[u] = v;
	}
	void cut(int u, int v){
		mkrt(u);
		if (qrt(v) == u && fa[v] == u && !ch[v][0]){
			ch[u][1] = 0;
			fa[v] = 0;
			pup(u);
		}
	}
}tr;
int n, q;
int main(){
	ios::sync_with_stdio(false);
	cin.tie(0);cout.tie(0);
	cin >> n >> q;
	for (int i = 1; i <= n; i++)
		cin >> tr.vl[i];
	while (q--){
		int op, u, v;
		cin >> op >> u >> v;
		if (op == 0){
			tr.split(u, v);
			cout << tr.sum[v] << "\n";
		}else if (op == 1)
			tr.link(u, v);
		else if (op == 2)
			tr.cut(u, v);
		else if (op == 3){
			tr.splay(u);
			tr.vl[u] = v;
		}
	}
	return 0;
}