bzoj2157: 旅游

又是lct裸题（据说暴力能过？）

写着略蛋疼

  1 #include<iostream>
  2 #include<cstring>
  3 #include<cstdlib>
  4 #include<cstdio>
  5 #include<algorithm>
  6
  7 using namespace std;
  8
  9 const int Maxn=200010;
 10
 11 int ch[Maxn][2],w[Maxn],sum[Maxn],mn[Maxn],mx[Maxn],p[Maxn];
 12 bool flip[Maxn],rev[Maxn];
 13
 14 bool isroot(int x) {
 15     return ch[p[x]][0]!=x && ch[p[x]][1]!=x;
 16 }
 17
 18 #define l ch[x][0]
 19 #define r ch[x][1]
 20 int n;
 21
 22 void update(int x) {
 23     if(!x) return;
 24     sum[x] = w[x] + sum[l] + sum[r];
 25     mn[x] = min(mn[l],mn[r]);
 26     mx[x] = max(mx[l],mx[r]);
 27     if(x>n) mn[x]=min(mn[x],w[x]),
 28             mx[x]=max(mx[x],w[x]);
 29 }
 30
 31 void rever(int x) {
 32     sum[x]*=-1;
 33     w[x]*=-1;
 34     swap(mn[x],mx[x]);
 35     mn[x]*=-1;
 36     mx[x]*=-1;
 37     rev[x]^=1;
 38 }
 39
 40 void down(int x) {
 41     if(!x) return;
 42     if(flip[x]) {
 43         swap(l,r);
 44         flip[l]^=1;
 45         flip[r]^=1;
 46         flip[x]^=1;
 47     }
 48     if(rev[x]) {
 49         rev[x] = 0;
 50         if(l) rever(l);
 51         if(r) rever(r);
 52     }
 53 }
 54
 55
 56 #undef l
 57 #undef r
 58
 59 void rotate(int x) {
 60     int y=p[x],z=p[y];
 61     if(!isroot(y)) ch[z][ch[z][1]==y] = x;
 62     int l=ch[y][1]==x,r=l^1;
 63     p[x]=z;
 64     p[y]=x;
 65     p[ch[x][r]]=y;
 66
 67     ch[y][l]=ch[x][r];
 68     ch[x][r]=y;
 69
 70     update(y);
 71     update(x);
 72 }
 73
 74 void splay(int x) {
 75     static int stk[Maxn],top;
 76     stk[top=1]=x;
 77     for(int t=x;!isroot(t);t=p[t]) stk[++top]=p[t];
 78     while(top) down(stk[top--]);
 79
 80     for(;!isroot(x);) {
 81         int y=p[x],z=p[y];
 82         if(!isroot(y)) {
 83             if( (ch[y][0]==x)^(ch[z][0]==y) )rotate(x);
 84             rotate(y);
 85         }
 86         rotate(x);
 87     }
 88 }
 89
 90 void access(int x) {
 91     for(int t=0;x;x=p[t=x]) {
 92         splay(x);
 93         ch[x][1]=t;
 94         update(x);
 95     }
 96 }
 97
 98 int getroot(int x) {
 99     for(access(x),splay(x);ch[x][0];x=ch[x][0]);
100     return x;
101 }
102
103 void newroot(int x) {
104     access(x);
105     splay(x);
106     flip[x]^=1;
107 }
108
109 void Link(int x,int y) {
110     newroot(x);
111     p[x]=y;
112 }
113
114 int m;
115 const int INF=int(1e9);
116 void init() {
117     scanf("%d",&n);
118     int u,v,W;
119     for(int i=0;i<=n;i++){
120         mn[i]=INF,mx[i]=-INF;
121     }
122     for(int i=1;i<n;i++) {
123         scanf("%d%d%d",&u,&v,&W);u++,v++;
124         w[i+n]=W;
125         Link(u,i+n),Link(v,i+n);
126     }
127 }
128
129 void work() {
130     char opt[100];
131     int x,y;
132     for(scanf("%d",&m);m--;) {
133         scanf("%s%d%d",opt,&x,&y);
134         if(opt[0]==‘C‘) {
135             access(x+n);
136             splay(x+n);
137             w[x+n]=y;
138             update(x+n);
139         }else if(opt[0]==‘N‘) {
140             x++,y++;
141             newroot(x);
142             access(y);
143             splay(y);
144             rever(y);
145         }else if(opt[0]==‘S‘) {
146             x++,y++;
147             newroot(x);
148             access(y);
149             splay(y);
150             printf("%d\n",sum[y]);
151         }else if(opt[0]==‘M‘&&opt[1]==‘A‘) {
152             x++,y++;
153             newroot(x);
154             access(y);
155             splay(y);
156             printf("%d\n",mx[y]);
157         }else /*if(opt[0]==e)*/ {
158             x++,y++;
159             newroot(x);
160             access(y);
161             splay(y);
162             printf("%d\n",mn[y]);
163         }
164     }
165 }
166
167 int main() {
168 #ifdef DEBUG
169     freopen("in.txt","r",stdin);
170     freopen("out.txt","w",stdout);
171 #endif
172
173     init();
174     work();
175
176     return 0;
177 }