#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/priority_queue.hpp>
#include <ext/pb_ds/exception.hpp>
#include <ext/pb_ds/hash_policy.hpp>
#include <ext/pb_ds/list_update_policy.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/trie_policy.hpp>
// using namespace __gnu_pbds;
// tree<int,null_type,less<int>,rb_tree_tag,tree_order_statistics_node_update>T;
using namespace std;
typedef long long ll;
typedef pair<ll, ll> pll;
typedef long double ldb;
//#define umap unordered_map
#define umap __gnu_pbds::cc_hash_table
#define mkp make_pair
#define prque priority_queue
#define emp emplace
#define empb emplace_back
#define empf emplace_front
random_device rndv;
mt19937 rd(rndv());
const ll inf = 0x3f3f3f3f3f3f3f3fll;
const double eps = 1e-8;
const vector<ll> millerrabin = {2, 325, 9375, 28178, 450775, 9780504, 1795265022};
inline void enter(){putchar('\n');}
inline void space(){putchar(' ');}
inline ll readll(){ll ret=0,k=1;char c;do{c=getchar();if(c=='-'){k=-1;}}while(('0'>c)|('9'<c));do{ret=(ret<<3)+(ret<<1)+c-48;c=getchar();}while(('0'<=c)&(c<='9'));return ret*k;}
inline void read(ll&x){x=readll();}
inline char readchar(){char ret;do{ret=getchar();}while(ret<=32);return ret;}
inline void read(char&x){x=readchar();}
inline string readstr(){string ret;char c;do{c=getchar();}while(c<=32);do{ret+=c;c=getchar();}while((c>32)&(c!=EOF));return ret;}
inline void read(string&x){x=readstr();}
inline void write(ll x){if(!x){putchar('0');return;}if(x<0){putchar('-');x*=-1;}char op[20]={};ll cur=0;while(x){op[++cur]=x%10+48;x/=10;}while(cur){putchar(op[cur--]);}}
inline ostream& operator<<(ostream& out, __int128 x){if(!x){out<<"0";return out;}if(x<0){out<<"-";x*=-1;}char op[40]={};ll cur=0;while(x){op[++cur]=x%10+48;x/=10;}while(cur){out<<op[cur--];}return out;}
// -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

const ll MAXN = 3e5 + 5;

struct LCTNode {
	ll l, r, p, xr, val, rev;
	LCTNode() {
		l = r = p = xr = val = rev = 0;
	}
};
struct LCT {
	LCTNode node[MAXN];
	void lock() {
		node[0] = LCTNode();
	}
	void pushup(ll x) {
		lock();
		node[x].xr = node[x].val ^ node[node[x].l].xr ^ node[node[x].r].xr;
	}
	void pushdown(ll x) {
		lock();
		if (node[x].rev) {
			swap(node[x].l, node[x].r);
		}
		node[node[x].l].rev ^= node[x].rev;
		node[node[x].r].rev ^= node[x].rev;
		lock();
		node[x].rev = 0;
	}
	bool isr(ll x) {
		lock();
		return x && node[node[x].p].l != x && node[node[x].p].r != x;
	}
	bool isl(ll x) {
		return x && !isr(x) && node[node[x].p].l == x;
	}
	void upd(ll x) {
		if (!isr(x)) {
			upd(node[x].p);
		}
		pushdown(x);
	}
	void rtt(ll x) {
		if (!x || isr(x)) {
			return;
		}
		ll p = node[x].p, g = node[p].p;
		pushdown(g), pushdown(p), pushdown(x);
		if (!isr(p)) {
			if (isl(p)) {
				node[g].l = x;
			} else {
				node[g].r = x;
			}
		}
		if (isl(x)) {
			node[p].l = node[x].r;
			node[node[x].r].p = p;
			node[x].r = p;
		} else {
			node[p].r = node[x].l;
			node[node[x].l].p = p;
			node[x].l = p;
		}
		node[p].p = x;
		node[x].p = g;
		pushup(p), pushup(x), pushup(g);
	}
	void spl(ll x) {
		if (!x) {
			return;
		}
		upd(x);
		while (!isr(x) && !isr(node[x].p)) {
			ll p = node[x].p;
			if (isl(p) == isl(x)) {
				rtt(p);
			} else {
				rtt(x);
			}
			rtt(x);
		}
		rtt(x);
	}
	void acc(ll x) {
		if (!x) {
			return;
		}
		for (ll s = 0; x; s = x, x = node[x].p) {
			spl(s), spl(x);
			node[x].r = s, node[s].p = x;
			lock();
			pushup(x);
		}
	}
	void mkr(ll x) {
		acc(x), spl(x);
		pushdown(x);
		node[x].rev = 1;
		pushdown(x);
	}
	void spt(ll x, ll y) {
		mkr(x), acc(y), spl(y);
	}
	ll fnd(ll x) {
		acc(x), spl(x);
		pushdown(x);
		while (node[x].l) {
			x = node[x].l;
			pushdown(x);
		}
// =========================================
		spl(x);
// =========================================
		return x;
	}
	void link(ll x, ll y) {
		if (fnd(x) == fnd(y)) {
			return;
		}
		mkr(x), mkr(y);
		node[y].p = x;
		pushup(y), pushup(x);
	}
	void cut(ll x, ll y) {
		if (fnd(x) != fnd(y)) {
			return;
		}
		spt(x, y);
		if (node[x].r) {
			return;
		}
		node[x].p = node[y].l = 0;
		pushup(x), pushup(y);
	}
	void setval(ll x, ll v) {
		spt(x, x);
		node[x].xr = node[x].val = v;
	}
	ll getval(ll x, ll y) {
		spt(x, y);
		return node[y].xr;
	}
} lct;

ll n, q;
int main() {
	read(n), read(q);
	for (ll i = 1; i <= n; ++i) {
		ll v;
		read(v);
		lct.setval(i, v);
	}
	while (q--) {
		ll o, x, y;
		read(o), read(x), read(y);
		if (o == 0) {
			write(lct.getval(x, y)), enter();
		} else if (o == 1) {
			lct.link(x, y);
		} else if (o == 2) {
			lct.cut(x, y);
		} else {
			lct.setval(x, y);
		}
	}
	return 0;
}

为什么代码第 149 行那个 splay 删掉就过不去样例 2