lct裸题．
记得很久之前打算学lct的时候看着好难啊．结果是水题．
调了半天去看了眼别人代码，发现取相反数的时候忘了把本身的v取反了．
1 //Achen
2 #include<algorithm>
3 #include<iostream>
4 #include<cstring>
5 #include<cstdio>
6 #include<queue>
7 #include<cmath>
8 const int N=4e4+7;
9 typedef long long LL;
10 using namespace std;
11 int n,q,tot,id[N],v[N],ch[N][2],p[N],is[N],mx[N],mi[N],sum[N],flip[N],lz[N],sz[N];
12 char o[20];
13
14 template<typename T>void read(T &x) {
15 char ch=getchar(); T f=1; x=0;
16 while(ch!='-'&&(ch<'0'||ch>'9')) ch=getchar();
17 if(ch=='-') f=-1,ch=getchar();
18 for(;ch>='0'&&ch<='9';ch=getchar()) x=x*10+ch-'0'; x*=f;
19 }
20
21 #define lc ch[x][0]
22 #define rc ch[x][1]
23 void update(int x) {
24 sz[x]=sz[lc]+sz[rc]+1;
25 sum[x]=sum[lc]+sum[rc]+v[x];
26 mx[x]=is[x]?-1e9:v[x];
27 mi[x]=is[x]?1e9:v[x];
28 if(lc) mx[x]=max(mx[x],mx[lc]),mi[x]=min(mi[x],mi[lc]);
29 if(rc) mx[x]=max(mx[x],mx[rc]),mi[x]=min(mi[x],mi[rc]);
30 }
31
32 void cg(int x) { lz[x]^=1; v[x]*=-1; swap(mx[x],mi[x]); mi[x]*=-1; mx[x]*=-1; sum[x]*=-1; }
33 void down(int x) {
34 if(lz[x]) {
35 lz[x]^=1;
36 if(lc) cg(lc);
37 if(rc) cg(rc);
38 }
39 if(flip[x]) {
40 if(lc) flip[lc]^=1;
41 if(rc) flip[rc]^=1;
42 swap(lc,rc);
43 flip[x]^=1;
44 }
45 }
46
47 int isroot(int x) {return (ch[p[x]][0]!=x&&ch[p[x]][1]!=x);}
48
49 void rotate(int x) {
50 int y=p[x],z=p[y],l=(x==ch[y][1]),r=l^1;
51 if(!isroot(y)) ch[z][y==ch[z][1]]=x; p[x]=z;
52 ch[y][l]=ch[x][r]; p[ch[x][r]]=y;
53 ch[x][r]=y; p[y]=x;
54 update(y); update(x);
55 }
56
57 void splay(int x) {
58 static int g[N],top=0,tp;
59 for(tp=x;!isroot(tp);tp=p[tp]) g[++top]=tp;
60 g[++top]=tp;
61 while(top) down(g[top--]);
62 for(;!isroot(x);rotate(x)) {
63 int y=p[x],z=p[y];
64 if(!isroot(y))
65 ((x==ch[y][1])^(y==ch[z][1]))?rotate(x):rotate(y);
66 }
67 }
68
69 void access(int x) {
70 for(int t=0;x;x=p[t=x]) {
71 splay(x);
72 rc=t;
73 update(x);
74 }
75 }
76
77 void newroot(int x) {
78 access(x);
79 splay(x);
80 flip[x]^=1;
81 }
82
83 void lik(int x,int y,int z) {
84 newroot(x);
85 splay(x);
86 newroot(y);
87 splay(y);
88 p[x]=p[y]=z;
89 }
90
91 int main() {
92 #ifdef orzllj
93 freopen("1.in","r",stdin);
94 #endif
95 read(n);
96 for(int i=1;i<=n;i++) {
97 v[++tot]=0;
98 mi[tot]=1e9; mx[tot]=-1e9;
99 is[tot]=1; sz[tot]=1;
100 }
101 for(int i=1;i<n;i++) {
102 int x,y,z,w;
103 read(x); read(y); read(w);
104 x++; y++;
105 z=++tot; v[z]=w; sz[z]=1;
106 lik(x,y,z); id[i]=tot;
107 }
108 read(q);
109 while(q--) {
110 scanf("%s",o);
111 if(o[0]=='C') {
112 int i,w;
113 read(i); read(w);
114 splay(id[i]);
115 v[id[i]]=w;
116 update(id[i]);;
117 }
118 else {
119 int x,y;
120 read(x); read(y);
121 x++; y++;
122 newroot(x);
123 access(y);
124 splay(y);
125 if(o[0]=='N') cg(y);
126 else if(o[0]=='S') printf("%d
",sum[y]);
127 else if(o[1]=='A') printf("%d
",mx[y]);
128 else if(o[1]=='I') printf("%d
",mi[y]);
129 }
130 }
131 return 0;
132 }
133 /*
134 3
135 0 1 1
136 1 2 2
137 8
138 SUM 0 2
139 MAX 0 2
140 N 0 1
141 SUM 0 2
142 MIN 0 2
143 C 1 3
144 SUM 0 2
145 MAX 0 2
146 */