【BZOJ3282】Tree【Link-Cut Tree】

模板题咯，WC前练下手。

#include <cstdio>
#include <algorithm>

using namespace std;

const int maxn = 300005;

int n, m, w[maxn], fa[maxn], son[maxn][2], sum[maxn];
bool rev[maxn];

inline int iread() {
	int f = 1, x = 0; char ch = getchar();
	for(; ch < '0' || ch > '9'; ch = getchar()) f = ch == '-' ? -1 : 1;
	for(; ch >= '0' && ch <= '9'; ch = getchar()) x = x * 10 + ch - '0';
	return f * x;
}

inline bool isroot(int x) {
	return son[fa[x]][0] != x && son[fa[x]][1] != x;
}

inline void pushup(int x) {
	sum[x] = w[x] ^ sum[son[x][0]] ^ sum[son[x][1]];
}

inline void pushdown(int x) {
	if(rev[x]) {
		rev[son[x][0]] ^= 1; rev[son[x][1]] ^= 1;
		swap(son[x][0], son[x][1]);
		rev[x] = 0;
	}
}

int st[maxn];
inline void maintain(int x) {
	int top = 0; st[++top] = x;
	for(; !isroot(x); x = fa[x]) st[++top] = fa[x];
	while(top) pushdown(st[top--]);
}

inline void rotate(int x) {
	int y = fa[x], z = fa[y], type = son[y][1] == x;
	fa[son[y][type] = son[x][!type]] = y;
	fa[x] = z;
	if(!isroot(y)) son[z][son[z][1] == y] = x;
	fa[son[x][!type] = y] = x;
	pushup(y); pushup(x);
}

inline void splay(int x) {
	maintain(x);
	while(!isroot(x)) {
		int y = fa[x], z = fa[y];
		if(isroot(y)) rotate(x);
		else if(son[z][0] == y ^ son[y][0] == x) rotate(x), rotate(x);
		else rotate(y), rotate(x);
	}
}

inline void access(int x) {
	for(int y = 0; x; x = fa[y = x]) {
		splay(x);
		son[x][1] = y;
		pushup(x);
	}
}

inline void makeroot(int x) {
	access(x); splay(x); rev[x] ^= 1;
}

inline int findroot(int x) {
	for(; !isroot(x); x = fa[x]);
	return x;
}

inline void link(int x, int y) {
	if(findroot(x) == findroot(y)) return;
	makeroot(x); fa[x] = y;
}

inline void cut(int x, int y) {
	makeroot(x); access(y); splay(y);
	if(son[y][0] == x) son[y][0] = fa[x] = 0;
}

inline void change(int x, int c) {
	makeroot(x); w[x] = c; pushup(x);
}

inline int query(int x, int y) {
	makeroot(x); access(y); splay(y);
	return sum[y];
}

int main() {
	n = iread(); m = iread();
	for(int i = 1; i <= n; i++) sum[i] = w[i] = iread();
	while(m--) {
		int opt = iread(), x = iread(), y = iread();
		if(opt == 1) link(x, y);
		else if(opt == 2) cut(x, y);
		else if(opt == 3) change(x, y);
		else if(x == y) printf("%d\n", w[x]);
		else printf("%d\n", query(x, y));
	}
	return 0;
}