HDU4547 CD操作 LCA

　　题目链接：http://acm.hdu.edu.cn/showproblem.php?pid=4547
　　去年区预赛网络赛的时候写过一到LCA的题目<HDU4409>，本来想用那份代码修改下来交这道题的，不过貌似难得修改，就重新写了ST+DFS的代码当模板用。跑了2078ms，应该是map的效率低了。。。
  1 //STATUS:C++_AC_2078MS_26116KB
  2 #include <functional>
  3 #include <algorithm>
  4 #include <iostream>
  5 //#include <ext/rope>
  6 #include <fstream>
  7 #include <sstream>
  8 #include <iomanip>
  9 #include <numeric>
 10 #include <cstring>
 11 #include <cassert>
 12 #include <cstdio>
 13 #include <string>
 14 #include <vector>
 15 #include <bitset>
 16 #include <queue>
 17 #include <stack>
 18 #include <cmath>
 19 #include <ctime>
 20 #include <list>
 21 #include <set>
 22 #include <map>
 23 using namespace std;
 24 //using namespace __gnu_cxx;
 25 //define
 26 #define pii pair<int,int>
 27 #define mem(a,b) memset(a,b,sizeof(a))
 28 #define lson l,mid,rt<<1
 29 #define rson mid+1,r,rt<<1|1
 30 #define PI acos(-1.0)
 31 //typedef
 32 typedef __int64 LL;
 33 typedef unsigned __int64 ULL;
 34 //const
 35 const int N= 200010;
 36 const int INF=0x3f3f3f3f;
 37 const int MOD=100000,STA=8000010;
 38 const LL LNF=1LL<<60;
 39 const double EPS=1e-8;
 40 const double OO=1e15;
 41 const int dx[4]={-1,0,1,0};
 42 const int dy[4]={0,1,0,-1};
 43 const int day[13]={0,31,28,31,30,31,30,31,31,30,31,30,31};
 44 //Daily Use ...
 45 inline int sign(double x){return (x>EPS)-(x<-EPS);}
 46 template<class T> T gcd(T a,T b){return b?gcd(b,a%b):a;}
 47 template<class T> T lcm(T a,T b){return a/gcd(a,b)*b;}
 48 template<class T> inline T lcm(T a,T b,T d){return a/d*b;}
 49 template<class T> inline T Min(T a,T b){return a<b?a:b;}
 50 template<class T> inline T Max(T a,T b){return a>b?a:b;}
 51 template<class T> inline T Min(T a,T b,T c){return min(min(a, b),c);}
 52 template<class T> inline T Max(T a,T b,T c){return max(max(a, b),c);}
 53 template<class T> inline T Min(T a,T b,T c,T d){return min(min(a, b),min(c,d));}
 54 template<class T> inline T Max(T a,T b,T c,T d){return max(max(a, b),max(c,d));}
 55 //End
 56 
 57 struct Edge{
 58     int u,v;
 59 }e[N];
 60 int first[N],next[N],f[N][20],d[N],E[N],R[N],vis[N];
 61 int T,n,m,mt,all,dis,root;
 62 map<string,int> q;
 63 
 64 void adde(int a,int b)
 65 {
 66     e[mt].u=a;e[mt].v=b;
 67     next[mt]=first[a],first[a]=mt++;
 68 }
 69 
 70 int Minele(int i,int j)
 71 {
 72     return d[i]<d[j]?i:j;
 73 }
 74 
 75 void rmq_init(int n)
 76 {
 77     int i,j;
 78     for(i=1;i<=n;i++)f[i][0]=i;
 79     for(j=1;(1<<j)<=n;j++){
 80         for(i=1;i+(1<<j)-1<=n;i++){
 81             f[i][j]=Minele(f[i][j-1],f[i+(1<<(j-1))][j-1]);
 82         }
 83     }
 84 }
 85 
 86 int rmq(int l,int r)
 87 {
 88     int k=0;
 89     while((1<<(k+1))<=r-l+1)k++;
 90     return Minele(f[l][k],f[r-(1<<k)+1][k]);
 91 }
 92 
 93 void dfs(int u,int deep)
 94 {
 95     d[dis]=deep;
 96     E[dis]=u;
 97     R[u]=dis++;
 98     int i;
 99     for(i=first[u];i!=-1;i=next[i]){
100         dfs(e[i].v,deep+1);
101         d[dis]=deep;
102         E[dis++]=u;
103     }
104 }
105 
106 void LCA_Init()
107 {
108     dis=1;
109     dfs(root,0);
110     rmq_init(dis-1);
111 }
112 
113 int LCA(int a,int b)
114 {
115     int left=R[a],right=R[b];
116     if(left>right)swap(left,right);
117     return E[rmq(left,right)];
118 }
119 
120 int main()
121 {
122  //   freopen("in.txt","r",stdin);
123     int i,j,fa,a,b;
124     char s1[42],s2[42];
125     scanf("%d",&T);
126     while(T--)
127     {
128         scanf("%d%d",&n,&m);
129         q.clear();all=1;
130         mem(first,-1);mt=0;
131         mem(vis,0);
132         while(--n){
133             scanf("%s%s",s1,s2);
134             if(!q[s1])q[s1]=all++;
135             if(!q[s2])q[s2]=all++;
136             vis[q[s1]]=1;
137             adde(q[s2],q[s1]);
138         }
139         for(i=1;i<all;i++)if(!vis[i]){root=i;break;}
140 
141         LCA_Init();
142         while(m--){
143             scanf("%s%s",s1,s2);
144             a=q[s1];b=q[s2];
145             fa=LCA(a,b);
146             printf("%d\n",d[R[a]]-d[R[fa]]+(d[R[b]]>d[R[fa]]));
147         }
148     }
149     return 0;
150 }