LCT
直到动手写拆边为点的时候才发现根本不会写……去orz了一下Hzwer（话说这题应该也用不着LCT吧……下次再换种姿势写一遍好了）
1 /************************************************************** 2 Problem: 2157 3 User: Tunix 4 Language: C++ 5 Result: Accepted 6 Time:668 ms 7 Memory:2600 kb 8 ****************************************************************/ 9 10 //BZOJ 2157 11 #include<vector> 12 #include<cstdio> 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 using namespace std; 21 int getint(){ 22 int v=0,sign=1; char ch=getchar(); 23 while(ch<'0'||ch>'9'){ if (ch=='-') sign=-1; ch=getchar();} 24 while(ch>='0'&&ch<='9'){ v=v*10+ch-'0'; ch=getchar();} 25 return v*=sign; 26 } 27 /******************tamplate*********************/ 28 const int N=40010,INF=~0u>>2; 29 int n,m,cnt; 30 int ed[N]; 31 int c[N][2],fa[N],v[N],sum[N],mn[N],mx[N]; 32 bool rev[N],Not[N]; 33 #define L c[x][0] 34 #define R c[x][1] 35 bool not_root(int x){ 36 return c[fa[x]][0]==x || c[fa[x]][1]==x; 37 } 38 void rever(int x){ 39 sum[x]=-sum[x]; v[x]=-v[x]; 40 swap(mn[x],mx[x]); 41 mn[x]=-mn[x];mx[x]=-mx[x]; 42 Not[x]^=1; 43 } 44 void Push_up(int x){ 45 mx[x]=max(mx[L],mx[R]); 46 mn[x]=min(mn[L],mn[R]); 47 if (x>n){ 48 mx[x]=max(mx[x],v[x]); 49 mn[x]=min(mn[x],v[x]); 50 } 51 sum[x]=sum[L]+sum[R]+v[x]; 52 } 53 void Push_down(int x){ 54 if (Not[x]){ 55 Not[x]^=1; 56 if (L) rever(L); 57 if (R) rever(R); 58 } 59 if (rev[x]){ 60 rev[x]^=1; rev[L]^=1; rev[R]^=1; 61 swap(L,R); 62 } 63 } 64 void rotate(int x){ 65 int y=fa[x],z=fa[y],l=c[y][1]==x,r=l^1; 66 if (not_root(y)) c[z][c[z][1]==y]=x; 67 fa[x]=z; fa[y]=x; fa[c[x][r]]=y; 68 c[y][l]=c[x][r]; c[x][r]=y; 69 Push_up(y); 70 } 71 void preview(int x){ 72 if (not_root(x)) preview(fa[x]); 73 Push_down(x); 74 } 75 void splay(int x){ 76 int y; 77 for(preview(x);not_root(x);rotate(x)) 78 not_root(y=fa[x]) ? rotate(c[y][1]==x^c[fa[y]][1]==y ? x : y),1:1; 79 Push_up(x); 80 } 81 void access(int x,int las=0){ 82 for(;x;splay(x),c[x][1]=las,las=x,x=fa[x]); 83 } 84 void makeroot(int x){ 85 access(x),splay(x),rev[x]^=1; 86 } 87 void link(int x,int y){ 88 makeroot(x),fa[x]=y; 89 } 90 void query(int x,int y){ 91 makeroot(x),access(y),splay(y); 92 } 93 int main(){ 94 n=getint(); 95 F(i,0,n) mn[i]=INF,mx[i]=-INF; 96 int id=n; 97 F(i,1,n-1){ 98 int x=getint()+1,y=getint()+1,w=getint(); 99 ed[i]=++id; 100 link(x,id); link(y,id); 101 v[id]=sum[id]=mx[id]=mn[id]=w; 102 } 103 m=getint(); 104 char cmd[5]; int x,y; 105 F(i,1,m){ 106 scanf("%s",cmd); 107 x=getint(); y=getint(); 108 if (cmd[0]=='C'){ 109 splay(ed[x]),v[ed[x]]=y,Push_up(ed[x]); 110 } 111 else if(cmd[0]=='N') 112 query(x+1,y+1),rever(y+1); 113 else if(cmd[0]=='S') 114 query(x+1,y+1),printf("%d ",sum[y+1]); 115 else if(cmd[1]=='A') 116 query(x+1,y+1),printf("%d ",mx[y+1]); 117 else query(x+1,y+1),printf("%d ",mn[y+1]); 118 } 119 return 0; 120 }