LCT

　　喜闻乐见的Link-Cut-Tree……

　　srO zyf

　　http://www.cnblogs.com/zyfzyf/p/4149109.html

　　目测我是第222个？………………不要在意这些细节……

　　和以前写的splay还是有些区别呢……

　　比如splay中Push_down的写法……还有rotate的新姿势~

　　算法看看论文什么的……很好懂

  1 /**************************************************************
  2     Problem: 3282
  3     User: Tunix
  4     Language: C++
  5     Result: Accepted
  6     Time:2596 ms
  7     Memory:8596 kb
  8 ****************************************************************/
  9
 10 //BZOJ 3282
 11 #include<cstdio>
 12 #include<vector>
 13 #include<cstring>
 14 #include<cstdlib>
 15 #include<iostream>
 16 #include<algorithm>
 17 #define rep(i,n) for(int i=0;i<n;++i)
 18 #define F(i,j,n) for(int i=j;i<=n;++i)
 19 #define D(i,j,n) for(int i=j;i>=n;--i)
 20 #define pb push_back
 21 using namespace std;
 22 const int N=300010;
 23 #define debug
 24
 25 int c[N][2],fa[N],v[N],s[N],st[N],top=0;
 26 bool rev[N];
 27 int n,m;
 28
 29 void Push_up(int x){
 30     int l=c[x][0],r=c[x][1];
 31     s[x]=s[l]^s[r]^v[x];
 32 }
 33 void Push_down(int x){
 34     int l=c[x][0],r=c[x][1];
 35     if(rev[x]){
 36         rev[x]^=1; rev[l]^=1; rev[r]^=1;
 37         swap(c[x][0],c[x][1]);
 38     }
 39 }
 40 bool isroot(int x){
 41     return c[fa[x]][0]!=x && c[fa[x]][1]!=x;
 42 }
 43 void rotate(int x){
 44     int y=fa[x],z=fa[y],l=c[y][1]==x,r=l^1;
 45     if (!isroot(y)) c[z][c[z][1]==y]=x;
 46     fa[x]=z; fa[y]=x; fa[c[x][r]]=y;
 47     c[y][l]=c[x][r]; c[x][r]=y;
 48     Push_up(y); Push_up(x);
 49 }
 50 void splay(int x){
 51     top=0; st[top++]=x;
 52     for(int i=x;!isroot(i);i=fa[i])
 53         st[top++]=fa[i];
 54     while(top--) Push_down(st[top]);
 55
 56     while(!isroot(x)){
 57         int y=fa[x],z=fa[y];
 58         if (!isroot(y)){
 59             if (c[y][0]==x^c[z][0]==y) rotate(x);
 60             else rotate(y);
 61         }
 62         rotate(x);
 63     }
 64 }
 65 void access(int x){
 66     for(int t=0;x;t=x,x=fa[x])
 67         splay(x),c[x][1]=t,Push_up(x);
 68 }
 69 void makeroot(int x){
 70     access(x); splay(x); rev[x]^=1;
 71 }
 72 int find(int x){
 73     access(x); splay(x);
 74     while(c[x][0]) x=c[x][0];
 75     return x;
 76 }
 77 void cut(int x,int y){
 78     makeroot(x); access(y); splay(y);
 79     if (c[y][0]==x) c[y][0]=fa[x]=0;
 80 }
 81 void link(int x,int y){
 82     makeroot(x); fa[x]=y;
 83 }
 84 //LCT end
 85 int main(){
 86     #ifndef ONLINE_JUDGE
 87     freopen("file.in","r",stdin);
 88 //  freopen("file.out","w",stdout);
 89     #endif
 90     scanf("%d%d",&n,&m);
 91     F(i,1,n) {scanf("%d",&v[i]); s[i]=v[i];}
 92
 93     int c,x,y;
 94     F(i,1,m){
 95         scanf("%d%d%d",&c,&x,&y);
 96         switch(c){
 97             case 0:makeroot(x); access(y); splay(y); printf("%d\n",s[y]);break;
 98             case 1:if (find(x)!=find(y)) link(x,y);break;
 99             case 2:if (find(x)==find(y)) cut(x,y);break;
100             case 3:access(x); splay(x); v[x]=y; Push_up(x);break;
101         }
102     }
103     return 0;
104 }