BZOJ2049: [Sdoi2008]Cave 洞穴勘测

  1 #include<cstdio>
  2 #include<cstdlib>
  3 #include<cmath>
  4 #include<cstring>
  5 #include<algorithm>
  6 #include<iostream>
  7 #include<vector>
  8 #include<map>
  9 #include<set>
 10 #include<queue>
 11 #include<string>
 12 #define inf 1000000000
 13 #define maxn 20000+1000
 14 #define maxm 500+100
 15 #define eps 1e-10
 16 #define ll long long
 17 #define pa pair<int,int>
 18 using namespace std;
 19 inline int read()
 20 {
 21     int x=0,f=1;char ch=getchar();
 22     while(ch<‘0‘||ch>‘9‘){if(ch==‘-‘)f=-1;ch=getchar();}
 23     while(ch>=‘0‘&&ch<=‘9‘){x=10*x+ch-‘0‘;ch=getchar();}
 24     return x*f;
 25 }
 26 int fa[maxn],c[maxn][2],sta[maxn],n,m;
 27 bool rev[maxn];
 28 inline bool isroot(int x)
 29 {
 30     return c[fa[x]][0]!=x&&c[fa[x]][1]!=x;
 31 }
 32 void rotate(int x)
 33 {
 34     int y=fa[x],z=fa[y],l=(c[y][1]==x),r=l^1;
 35     if(!isroot(y))c[z][c[z][1]==y]=x;
 36     fa[x]=z;fa[y]=x;fa[c[x][r]]=y;
 37     c[y][l]=c[x][r];c[x][r]=y;
 38 }
 39 void pushdown(int x)
 40 {
 41     if(!rev[x])return;
 42     rev[x]^=1;rev[c[x][0]]^=1;rev[c[x][1]]^=1;
 43     swap(c[x][0],c[x][1]);
 44 }
 45 void splay(int x)
 46 {
 47     int top=0;sta[++top]=x;
 48     for(int y=x;!isroot(y);y=fa[y])sta[++top]=fa[y];
 49     for(;top;)pushdown(sta[top--]);
 50     while(!isroot(x))
 51     {
 52         int y=fa[x],z=fa[y];
 53         if(!isroot(y))
 54          {
 55              if(c[z][0]==y^c[y][0]==x)rotate(x);else rotate(y);
 56          }
 57         rotate(x); 
 58     }
 59     
 60 }
 61 void access(int x)
 62 {
 63     for(int y=0;x;x=fa[x])
 64     {
 65         splay(x);c[x][1]=y;y=x;
 66     }
 67 }
 68 void makeroot(int x)
 69 {
 70     access(x);splay(x);rev[x]^=1;
 71 }
 72 int find(int x)
 73 {
 74     access(x);splay(x);
 75     while(c[x][0])x=c[x][0];
 76     return x;
 77 }
 78 void link(int x,int y)
 79 {
 80     makeroot(x);fa[x]=y;splay(x);
 81 }
 82 void cut(int x,int y)
 83 {
 84     makeroot(x);access(y);splay(y);c[y][0]=fa[x]=0;
 85 }
 86 int main()
 87 {
 88     freopen("input.txt","r",stdin);
 89     freopen("output.txt","w",stdout);
 90     n=read();m=read();
 91     char ch[10];int x,y;
 92     while(m--)
 93     {
 94         scanf("%s",ch);x=read();y=read();
 95         switch(ch[0])
 96         {
 97             case ‘C‘:link(x,y);break;
 98             case ‘D‘:cut(x,y);break;
 99             case ‘Q‘:{if(find(x)==find(y))printf("Yes\n");else printf("No\n");}break;
100         }
101     }
102     return 0;
103 }