第一次写lct
（这是一道lct裸题
这次没有可爱（划掉）的同学教我，虽然有模板，但是配合网上的讲解还是看不懂QAQ
然后做了几道题之后总算有些感觉辣
于是决定给自己挖个坑，近期写一个lct详解（不过像我这么懒的人= =
下面是代码
1 /************************************************************** 2 Problem: 2049 3 User: cminus 4 Language: C++ 5 Result: Accepted 6 Time:1532 ms 7 Memory:984 kb 8 ****************************************************************/ 9 10 #include <cstdio> 11 #include <algorithm> 12 #include <stack> 13 using namespace std; 14 #define kd(x) (ch[fa[x]][1] == x) 15 #define setc(f, c, k) (ch[fa[c] = f][k] = c) 16 #define isRoot(x) (ch[fa[x]][0] != x and ch[fa[x]][1] != x) 17 #define ls ch[x][0] 18 #define rs ch[x][1] 19 const int N = 10020; 20 21 int fa[N], ch[N][2], n, m; 22 bool mark[N]; 23 24 inline void push(int x){ 25 if (mark[x]){ 26 mark[x] = false; 27 mark[ls] ^= 1; 28 mark[rs] ^= 1; 29 swap(ls, rs); 30 } 31 } 32 stack < int > S; 33 inline void pushDown(int x) { 34 S.push(x); 35 while (!isRoot(x)) 36 S.push(x = fa[x]); 37 while (!S.empty()) 38 push(S.top()), S.pop(); 39 } 40 41 inline void rotate (int x) { 42 int y = fa[x], k = kd(x); 43 setc(y, ch[x][k ^ 1], k); 44 if (isRoot(y)) fa[x] = fa[y]; 45 else setc(fa[y], x, kd(y)); 46 setc(x, y, k ^ 1); 47 } 48 49 inline void splay (int x) { 50 pushDown(x); 51 while (! isRoot(x)) { 52 if (! isRoot(fa[x])) 53 if (kd(x) == kd(fa[x])) rotate(fa[x]); 54 else rotate(x);rotate(x); 55 } 56 } 57 58 inline void access(int x) { 59 int t = 0; 60 while (x) { 61 splay(x); 62 rs = t; t = x; x = fa[x]; 63 } 64 } 65 66 inline void makeRoot(int u) { 67 access(u); splay(u); 68 mark[u] ^= 1; 69 } 70 71 inline void link(int u, int v){ 72 makeRoot(u); fa[u] = v; 73 } 74 75 inline void cut(int u, int v){ 76 makeRoot(u); 77 access(v); splay(v); 78 fa[u] = ch[v][0] = 0; 79 } 80 81 inline int findRoot(int x) { 82 while(fa[x]) x = fa[x]; 83 return x; 84 } 85 int main(){ 86 scanf("%d %d", &n, &m); 87 char str[20]; 88 while(m--){ 89 int u, v; 90 scanf("%s %d %d", str, &u, &v); 91 if (*str == 'C') link(u, v); 92 else if (*str == 'D') cut(u, v); 93 else puts((findRoot(u) == findRoot(v)) ? "Yes" : "No"); 94 } 95 return 0; 96 }