跟随ZYP巨佬的步伐学习了一下LCT。
最大的不同是它有了实边和虚边之分。
这里推荐一篇学习的博客，[FlashHu 的博客]
Code：
1 #include <bits/stdc++.h> 2 #define ls t[x][0] 3 #define rs t[x][1] 4 using namespace std; 5 const int N = 3e5 + 7; 6 int read() { 7 int re = 0, f = 1; 8 char ch = getchar(); 9 while (ch < '0' || ch > '9') {if (ch == '-') f = -f; ch = getchar();} 10 while ('0' <= ch && ch <= '9') {re = re * 10 + ch - '0'; ch = getchar();} 11 return re * f; 12 } 13 int n, m; 14 bool rev[N]; 15 int t[N][2], fa[N], val[N], s[N], stk[N]; 16 bool isroot(int x) { 17 return t[fa[x]][0] == x || t[fa[x]][1] == x; 18 } 19 void pushup(int x) { 20 s[x] = s[ls] ^ s[rs] ^ val[x]; 21 } 22 void reverse(int x) { 23 rev[x] ^= 1; 24 swap(ls, rs); 25 } 26 void pushdown(int x) { 27 if (rev[x]) { 28 if (ls) reverse(ls); 29 if (rs) reverse(rs); 30 rev[x] = 0; 31 } 32 } 33 int identify(int x) { 34 return t[fa[x]][1] == x; 35 } 36 void connect(int x, int father, int Son) { 37 fa[x] = father; 38 t[father][Son] = x; 39 } 40 void rotate(int x) { 41 int y = fa[x], fason = identify(x); 42 int gfa = fa[y], gfason = identify(y); 43 int B = t[x][fason ^ 1]; 44 fa[x] = fa[y]; 45 if (isroot(y)) connect(x, gfa, gfason); 46 connect(B, y, fason), connect(y, x, fason ^ 1); 47 pushup(y), pushup(x); 48 } 49 void splay(int x) { 50 int y = x, top = 0; 51 stk[++top] = y; 52 while (isroot(y)) stk[++top] = fa[y], y = fa[y]; 53 while (top) pushdown(stk[top--]); 54 while (isroot(x)) { 55 y = fa[x], top = fa[y]; 56 if (isroot(y)) { 57 rotate((t[y][0] == x) ^ (t[top][0] == y) ? x : y); 58 } 59 rotate(x); 60 } 61 pushup(x); 62 } 63 void access(int x) { 64 for (int y = 0; x; y = x, x = fa[x]) { 65 splay(x), rs = y, pushup(x); 66 } 67 } 68 void makeroot(int x) { 69 access(x), splay(x), reverse(x); 70 } 71 int findroot(int x) { 72 access(x), splay(x); 73 while (ls) pushdown(x), x = ls; 74 splay(x); 75 return x; 76 } 77 void split(int x, int y) { 78 makeroot(x); 79 access(y), splay(y); 80 } 81 void link(int x, int y) { 82 makeroot(x); 83 if (findroot(y) != x) fa[x] = y; 84 } 85 void cut(int x, int y) { 86 makeroot(x); 87 if (findroot(y) == x && fa[y] == x && !t[y][0]) { 88 fa[y] = t[x][1] = 0; 89 pushup(x); 90 } 91 } 92 int main () { 93 n = read(), m = read(); 94 for (int i = 1; i <= n; i++) { 95 val[i] = read(); 96 } 97 while (m--) { 98 int o = read(), x = read(), y = read(); 99 if (o == 0) { 100 split(x, y); 101 printf("%d ", s[y]); 102 } else if (o == 1) { 103 link(x, y); 104 } else if (o == 2) { 105 cut(x, y); 106 } else { 107 splay(x); 108 val[x] = y; 109 } 110 } 111 return 0; 112 }