CD操作
http://acm.hdu.edu.cn/showproblem.php?pid=4547
C++版本一
題解：
LCA樹上倍增
注意：CD 向下走可以一步到底
/* *@Author: STZG *@Language: C++ */ #include <bits/stdc++.h> #include<iostream> #include<algorithm> #include<cstdlib> #include<cstring> #include<cstdio> #include<string> #include<vector> #include<bitset> #include<queue> #include<deque> #include<stack> #include<cmath> #include<list> #include<map> #include<set> //#define DEBUG #define RI register int #define endl "\n" using namespace std; typedef long long ll; //typedef __int128 lll; const int N=100000+10; const int M=100000+10; const int MOD=1e9+7; const double PI = acos(-1.0); const double EXP = 1E-8; const int INF = 0x3f3f3f3f; int t,n,m,k,p,l,r,u,v,c; int ans,cnt,flag,temp,tot,sum,num; int pre[N]; bool vis[N]; int dep[N]; int dp[N][21]; string str,str1; struct node{int v,w; }x; map<string,int>mp; vector<int>G[N]; int find(int x){return pre[x]==x?x:pre[x]=find(pre[x]);} void marge(int u,int v){int tu=find(u);int tv=find(v);if(tu!=tv){pre[tu]=tv;} } void dfs(int u){vis[u]=1;for(int i=0,j=G[u].size();i<j;i++){int v=G[u][i];if(!vis[v]){dep[v]=dep[u]+1;dp[v][0]=u;dfs(v);}} } void init(){for(int i=1;i<=n;i++){G[i].clear();pre[i]=i;}memset(vis,0,sizeof(vis));memset(dep,0,sizeof(dep));memset(dp,0,sizeof(dp));cnt=0,num=0;tot=0;mp.clear(); } int LCA(int x,int y){if(dep[x]<dep[y])swap(x,y);//cout<<x<<" "<<dp[1][0]<<endl;while(dep[x]>dep[y])x=dp[x][(int)log2(dep[x]-dep[y])];if(x==y)return x;for(int i=log2(dep[x]);i>=0;i--){if(dp[x][i]!=dp[y][i])x=dp[x][i],y=dp[y][i];}return dp[x][0]; } int main() { #ifdef DEBUGfreopen("input.in", "r", stdin);//freopen("output.out", "w", stdout); #endif//ios::sync_with_stdio(false);//cin.tie(0);//cout.tie(0);scanf("%d",&t);while(t--){scanf("%d%d",&n,&m);init();for(int i=1;i<n;i++){cin>>str>>str1;if(!mp[str])mp[str]=++tot;if(!mp[str1])mp[str1]=++tot;u=mp[str];v=mp[str1];G[u].push_back(v);G[v].push_back(u);marge(u,v);}//cout<<"1"<<endl;for(int i=1;i<=n;i++){if(pre[i]==i){dfs(i);}}//cout<<"2"<<endl;for(int i=0;i<20;i++){for(int j=1;j<=n;j++){dp[j][i+1]=dp[dp[j][i]][i];}}for(int i=1;i<=m;i++){cin>>str>>str1;u=mp[str];v=mp[str1];int lca=LCA(u,v);if(lca!=v){cout<<dep[u]-dep[lca]+1<<endl;}else{cout<<dep[u]-dep[lca]<<endl;}}}#ifdef DEBUGprintf("Time cost : %lf s\n",(double)clock()/CLOCKS_PER_SEC); #endif//cout << "Hello world!" << endl;return 0; }C++版本二
題解：LCA轉RMQ
卡著內存過的
/* *@Author: STZG *@Language: C++ */ #include <bits/stdc++.h> #include<iostream> #include<algorithm> #include<cstdlib> #include<cstring> #include<cstdio> #include<string> #include<vector> #include<bitset> #include<queue> #include<deque> #include<stack> #include<cmath> #include<list> #include<map> #include<set> //#define DEBUG #define RI register int #define endl "\n" using namespace std; typedef long long ll; //typedef __int128 lll; const int N=100000+10; const int M=100000+10; const int MOD=1e9+7; const double PI = acos(-1.0); const double EXP = 1E-8; const int INF = 0x3f3f3f3f; int t,n,m,k,p,l,r,u,v,c; int ans,cnt,flag,temp,tot,sum,num; int pre[N]; bool vis[N]; int dep[N<<1]; int dp[N<<1][18]; int que[N<<1]; int frist[N]; string str,str1; map<string,int>mp; vector<int>G[N]; int find(int x){return pre[x]==x?x:pre[x]=find(pre[x]);} void marge(int u,int v){int tu=find(u);int tv=find(v);if(tu!=tv){pre[tu]=tv;} } void dfs(int u,int deep){vis[u]=1;que[++num]=u;frist[u]=num;dep[num]=deep;for(int i=0,j=G[u].size();i<j;i++){int v=G[u][i];if(!vis[v]){dfs(v,deep+1);que[++num]=u;dep[num]=deep;}} } void init(){for(int i=1;i<=n;i++){G[i].clear();pre[i]=i;}memset(vis,0,sizeof(vis));memset(dep,0,sizeof(dep));memset(dp,0,sizeof(dp));memset(frist,0,sizeof(frist));memset(que,0,sizeof(que));cnt=0,num=0;tot=0;mp.clear(); } void ST(int n){for(int i=1;i<=n;i++){dp[i][0]=i;}for(int i=0;(1<<i)<n;i++){for(int j=1;j+(1<<i)<=n;j++){int a=dp[j][i],b=dp[j+(1<<i)][i];dp[j][i+1]=dep[a]<dep[b]?a:b;}} } int RMQ(int l,int r){int k=log2(r-l+1);int a=dp[l][k],b=dp[r-(1<<k)+1][k];return dep[a]<dep[b]?a:b; }int LCA(int u,int v){int x=frist[u],y=frist[v];if(x>y)swap(x,y);int res=RMQ(x,y);return que[res]; } int main() { #ifdef DEBUGfreopen("input.in", "r", stdin);//freopen("output.out", "w", stdout); #endif//ios::sync_with_stdio(false);//cin.tie(0);//cout.tie(0);scanf("%d",&t);while(t--){scanf("%d%d",&n,&m);init();for(int i=1;i<n;i++){cin>>str>>str1;if(!mp[str])mp[str]=++tot;if(!mp[str1])mp[str1]=++tot;u=mp[str];v=mp[str1];//G[u].push_back(v);G[v].push_back(u);marge(u,v);}//cout<<"1"<<endl;for(int i=1;i<=n;i++){if(pre[i]==i){dfs(i,0);}}//cout<<"2"<<endl;ST(2*n-1);for(int i=1;i<=m;i++){cin>>str>>str1;u=mp[str];v=mp[str1];int lca=LCA(u,v);int x=frist[u],y=frist[v],z=frist[lca];//cout<<u<<v<<lca<<endl;//cout<<x<<y<<z<<endl;//cout<<dep[x]<<dep[y]<<dep[z]<<endl;//cout<<que[x]<<que[y]<<que[z]<<endl;if(lca!=v){cout<<dep[x]-dep[z]+1<<endl;}else{cout<<dep[x]-dep[z]<<endl;}}}#ifdef DEBUGprintf("Time cost : %lf s\n",(double)clock()/CLOCKS_PER_SEC); #endif//cout << "Hello world!" << endl;return 0; }C++版本三
題解：Tarjan算法
#include<bits/stdc++.h> using namespace std; #define MAXN 100010 #define MAXL 45struct Edge {int to,nxt; } e[MAXN];int i,T,tot,id,n,m,root; int head[MAXN],dep[MAXN],f[MAXN],lca[MAXN],fa[MAXN]; string a,b; string x[MAXN],y[MAXN]; bool visited[MAXN]; map<string,int> mp; vector< pair<int,int> > query[MAXN];inline void add(int u,int v) {tot++;e[tot] = (Edge){v,head[u]};head[u] = tot; } inline void init(int u) {int i,v;for (i = head[u]; i; i = e[i].nxt){v = e[i].to;dep[v] = dep[u] + 1;init(v);} } inline int find(int x) {if (f[x] == x) return x;return f[x] = find(f[x]); } inline void tarjan(int u) {int i,v,pos;visited[u] = true;f[u] = u;for (i = 0; i < query[u].size(); i++){v = query[u][i].first;pos = query[u][i].second;if (visited[v]) lca[pos] = find(v);}for (i = head[u]; i; i = e[i].nxt){v = e[i].to;tarjan(v);f[v] = u;} }int main() {ios :: sync_with_stdio(0);cin.tie(0);cin >> T;while (T--){cin >> n >> m;tot = id = 0;mp.clear();for (i = 1; i <= n; i++){head[i] = 0;fa[i] = 0;visited[i] = false;query[i].clear();}for (i = 1; i < n; i++) {cin >> a >> b;if (!mp[a]) mp[a] = ++id;if (!mp[b]) mp[b] = ++id; add(mp[b],mp[a]);fa[mp[a]] = mp[b];} for (i = 1; i <= n; i++) {if (!fa[i])root = i;}dep[root] = 0;init(root);for (i = 1; i <= m; i++) {cin >> x[i] >> y[i];query[mp[x[i]]].push_back(make_pair(mp[y[i]],i));query[mp[y[i]]].push_back(make_pair(mp[x[i]],i));}tarjan(root);for (i = 1; i <= m; i++) {if (x[i] == y[i]) printf("%d\n",0);else if (lca[i] == mp[x[i]]) printf("%d\n",1);else if (lca[i] == mp[y[i]]) printf("%d\n",dep[mp[x[i]]]-dep[mp[y[i]]]);else printf("%d\n",dep[mp[x[i]]]-dep[lca[i]]+1);}}return 0;}C++版本四
題解：Tarjan算法
/* *@Author: STZG *@Language: C++ */ #include <bits/stdc++.h> #include<iostream> #include<algorithm> #include<cstdlib> #include<cstring> #include<cstdio> #include<string> #include<vector> #include<bitset> #include<queue> #include<deque> #include<stack> #include<cmath> #include<list> #include<map> #include<set> //#define DEBUG #define RI register int #define endl "\n" using namespace std; typedef long long ll; //typedef __int128 lll; const int N=200000+10; const int M=100000+10; const int MOD=1e9+7; const double PI = acos(-1.0); const double EXP = 1E-8; const int INF = 0x3f3f3f3f; int t,n,m,k,q,w,v,u; int ans,cnt,flag,temp,sum,tot; int pre[N]; bool vis[N]; int dep[N]; int ANS[N]; struct query{int u,v,id; }e[N],y; string str,str1; map<string,int>mp; vector<int>G[N]; vector<query>Q[N]; int find(int x){return pre[x]==x?x:pre[x]=find(pre[x]);} void marge(int u,int v){int tu=find(u);int tv=find(v);if(tu!=tv){pre[tu]=tv;} } void Tarjan(int u){//marge和find為并查集合并函數和查找函數//cout<<u<<endl;vis[u]=1;for(int i=0,j=G[u].size();i<j;i++) { //訪問所有u子節點vint v=G[u][i];if(vis[v])continue;dep[v]=dep[u]+1;Tarjan(v); //繼續往下遍歷marge(v,u); //合并v到u上//cout<<dep[v]<<endl;}for(int i=0,j=Q[u].size();i<j;i++){ //訪問所有和u有詢問關系的eint e=Q[u][i].v;int id=Q[u][i].id;int ID=(id+1)/2;if(vis[e]){int lca=find(e);//cout<<lca<<endl;if(id%2){if(lca!=e){ANS[ID]=dep[u]-dep[lca]+1;}else{ANS[ID]=dep[u]-dep[lca];}}else{if(lca!=u){ANS[ID]=dep[e]-dep[lca]+1;}else{ANS[ID]=dep[e]-dep[lca];}}}} } void init(){for(int i=1;i<=n;i++){pre[i]=i;G[i].clear();Q[i].clear();}memset(vis,0,sizeof(vis));memset(dep,0,sizeof(dep));memset(ANS,0x3f,sizeof(ANS));tot=0;mp.clear(); } int main() { #ifdef DEBUGfreopen("input.in", "r", stdin);//freopen("output.out", "w", stdout); #endif//ios::sync_with_stdio(false);//cin.tie(0);//cout.tie(0);scanf("%d",&t);while(t--){scanf("%d%d",&n,&m);init();for(int i=1;i<n;i++){cin>>str>>str1;if(!mp[str])mp[str]=++tot;if(!mp[str1])mp[str1]=++tot;u=mp[str];v=mp[str1];G[u].push_back(v);G[v].push_back(u);marge(u,v);}for(int i=1;i<=m;i++){cin>>str>>str1;if(!mp[str])mp[str]=++tot;if(!mp[str1])mp[str1]=++tot;//n==1時u=mp[str];v=mp[str1];y.v=v;y.id=2*i-1;Q[u].push_back(y);y.v=u;y.id=2*i;Q[v].push_back(y);}int root=0;for(int i=1;i<=n;i++){if(pre[i]==i){//Tarjan(i);root=i;break;}}for(int i=1;i<=n;i++){pre[i]=i;}Tarjan(root);for(int i=1;i<=m;i++){cout<<ANS[i]<<endl;}}#ifdef DEBUGprintf("Time cost : %lf s\n",(double)clock()/CLOCKS_PER_SEC); #endif//cout << "Hello world!" << endl;return 0; }?
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