hdu 4547 lca-tarjan离线算法

题意：

Problem Description

　　在Windows下我们可以通过cmd运行DOS的部分功能，其中CD是一条很有意思的命令，通过CD操作，我们可以改变当前目录。
　　这里我们简化一下问题，假设只有一个根目录，CD操作也只有两种方式：
　　
　　1. CD 当前目录名\...\目标目录名 (中间可以包含若干目录，保证目标目录通过绝对路径可达)
　　2. CD .. (返回当前目录的上级目录)
　　
　　现在给出当前目录和一个目标目录，请问最少需要几次CD操作才能将当前目录变成目标目录？

 

Input

输入数据第一行包含一个整数T(T<=20)，表示样例个数；
每个样例首先一行是两个整数N和M(1<=N,M<=100000)，表示有N个目录和M个询问；
接下来N-1行每行两个目录名A B(目录名是只含有数字或字母，长度小于40的字符串)，表示A的父目录是B。
最后M行每行两个目录名A B，表示询问将当前目录从A变成B最少要多少次CD操作。
数据保证合法，一定存在一个根目录，每个目录都能从根目录访问到。

 

Output

请输出每次询问的结果，每个查询的输出占一行。

 

Sample Input

23 1B AC AB C3 2B AC BA CC A

 

Sample Output

212

解析：

错了一个下午，用各种姿势wa。

不知道为什么一定要按照问题的id去排最后的ans。

难道输出就不是有序的吗。。。

就算是这里的问题，st在线算法还是wa。。。无言以对，不知道什么数据卡了。

代码：

换了上一题的模板，稳多了，wa了两发是因为数组开小了（╯＾╰）

ac：

#include <iostream>#include <cstdio>#include <cstdlib>#include <algorithm>#include <cstring>#include <cmath>#include <stack>#include <vector>#include <queue>#include <map>#include <set>#include <climits>#include <cassert>#define Min(a,b) ((a)<(b)?(a):(b))#define Max(a,b) ((a)>(b)?(a):(b))#define LL long long#define lson lo, mi, rt << 1#define rson mi + 1, hi, rt << 1 | 1using namespace std;const int inf = 0x3f3f3f3f;const double eps = 1e-8;const double pi = acos(-1.0);const double ee = exp(1.0);const int maxn = 100000 + 10;vector<pair<int, int> > ansQue;int ind[maxn];map<string, int> mp;int dis[maxn], vis[maxn], ancestor[maxn];int ans[maxn];struct Edge{    int to, next;    int len;} edge[maxn << 1];int edgeNum;int edgeHead[maxn << 1];void addEdge(int fr, int to, int len){    edge[edgeNum].to = to;    edge[edgeNum].len = len;    edge[edgeNum].next = edgeHead[fr];    edgeHead[fr] = edgeNum++;    edge[edgeNum].to = fr;    edge[edgeNum].len = len;    edge[edgeNum].next = edgeHead[to];    edgeHead[to] = edgeNum++;}struct Query{    int to, next;    int id;} query[maxn << 1];int queryNum;int queryHead[maxn << 1];void addQuery(int fr, int to, int id){    query[queryNum].to = to;    query[queryNum].id = id;    query[queryNum].next = queryHead[fr];    queryHead[fr] = queryNum++;    query[queryNum].to = fr;    query[queryNum].id = id;    query[queryNum].next = queryHead[to];    queryHead[to] = queryNum++;}int Find(int x){    if (ancestor[x] == x)        return x;    return ancestor[x] = Find(ancestor[x]);}void lca(int u, int dep, int rt){    ancestor[u] = u;    vis[u] = rt;    dis[u] = dep;    for (int i = edgeHead[u]; i != -1; i = edge[i].next)    {        int v = edge[i].to;        if (vis[v] == -1)        {            lca(v, dep + edge[i].len, rt);            ancestor[v] = u;        }    }    for (int i = queryHead[u]; i != -1; i = query[i].next)    {        int v = query[i].to;        if (vis[v] == rt)        {            ans[query[i].id] = ancestor[Find(v)];        }    }}void init(){    edgeNum = 0;    queryNum = 0;    memset(edgeHead, -1, sizeof(edgeHead));    memset(queryHead, -1, sizeof(queryHead));    memset(vis, -1, sizeof(vis));    memset(ans, -1, sizeof(ans));    memset(ind, 0, sizeof(ind));    ansQue.clear();    mp.clear();}int main(){#ifdef LOCAL    freopen("in.txt", "r", stdin);#endif // LOCAL    int ncase;    scanf("%d", &ncase);    while (ncase--)    {        int n, m;        scanf("%d%d", &n, &m);        init();        int tot = 1;        for (int i = 1; i < n; i++)        {            string a, b;            cin >> a >> b;            if (mp.find(a) == mp.end())            {                mp[a] = tot++;            }            if (mp.find(b) == mp.end())            {                mp[b] = tot++;            }            addEdge(mp[b], mp[a], 1);            ind[mp[a]]++;        }        for (int i = 0; i < m; i++)        {            string a, b;            cin >> a >> b;            ans[i] = -1;            addQuery(mp[a], mp[b], i);            ansQue.push_back(make_pair(mp[a], mp[b]));        }        int rt;        for (int i = 1; i <= n; i++)        {            if (!ind[i])            {                rt = i;                break;            }        }        lca(rt, 0, rt);        for (int i = 0; i < m; i++)        {            int fr = ansQue[i].first;            int to = ansQue[i].second;            if (fr == to)            {                printf("0\n");            }            else if (fr == ans[i])            {                printf("1\n");            }            else if (to == ans[i])            {                printf("%d\n", dis[fr] - dis[to]);            }            else            {                printf("%d\n", dis[fr] - dis[ans[i]] + 1);            }        }    }    return 0;}

ac：

#include <iostream>#include <cstdio>#include <cstdlib>#include <algorithm>#include <cstring>#include <cmath>#include <stack>#include <vector>#include <queue>#include <map>#include <set>#include <climits>#include <cassert>#define Min(a,b) ((a)<(b)?(a):(b))#define Max(a,b) ((a)>(b)?(a):(b))#define LL long long#define lson lo, mi, rt << 1#define rson mi + 1, hi, rt << 1 | 1using namespace std;const int maxn = 100000 + 10;const int inf = 0x3f3f3f3f;const double eps = 1e-8;const double pi = acos(-1.0);const double ee = exp(1.0);///int ans[maxn];vector<pair<int, int> > ansQue;struct Query{    int to, id;    Query(){}    Query(int _to, int _id)    {        to = _to;        id = _id;    }};map<string, int> mp;int step[maxn];int n;vector<int> edge[maxn];vector<Query> query[maxn];int inDegree[maxn];int ancestor[maxn];bool vis[maxn];int fa[maxn];int Rank[maxn];void Init(int n){    mp.clear();    ansQue.clear();    for (int i = 1; i <= n; i++)    {        fa[i] = i;        Rank[i] = 0;        edge[i].clear();        query[i].clear();    }    memset(vis, false, sizeof(vis));    memset(inDegree, 0, sizeof(inDegree));    memset(ancestor, 0, sizeof(ancestor));    memset(step, 0, sizeof(step));}int Find(int x){    if (fa[x] != x)        fa[x] = Find(fa[x]);    return fa[x];}void Union(int u, int v){    int fau = Find(u);    int fav = Find(v);    if (fau == fav)        return;    if (Rank[fau] < Rank[fav])    {        fa[fau] = fav;    }    else    {        fa[fav] = fau;        if (Rank[fau] == Rank[fav])            Rank[fau]++;    }}void lca(int rt, int num){    //自成集合    step[rt] = num;    ancestor[rt] = rt;    int sz = edge[rt].size();    for (int i = 0; i < sz; i++)    {        int v = edge[rt][i];        lca(v, num + 1);                    //递归子树        Union(rt, v);                       //合并子树与根        ancestor[Find(v)] = rt;             //子树祖先也指向根    }    vis[rt] = true;    sz = query[rt].size();    for (int i = 0; i < sz; i++)    {        int fr = rt;        int to = query[rt][i].to;        int id = query[rt][i].id;        if (vis[to])        {            ///记录答案时必须要这样。。。否则wa到死。。。            ///ps.I don't know why...            ans[id] = ancestor[Find(to)];        }    }    return;}int main(){#ifdef LOCAL    freopen("in.txt", "r", stdin);#endif // LOCAL    int ncase;    scanf("%d", &ncase);    while (ncase--)    {        int n, m;        scanf("%d%d", &n, &m);        Init(n);        int tot = 1;        for (int i = 1; i < n; i++)        {            string a, b;            cin >> a >> b;            if (mp.find(a) == mp.end())            {                mp[a] = tot++;            }            if (mp.find(b) == mp.end())            {                mp[b] = tot++;            }            edge[mp[b]].push_back(mp[a]);            inDegree[mp[a]]++;        }        for (int i = 0; i < m; i++)        {            string a, b;            cin >> a >> b;            query[mp[a]].push_back(Query(mp[b], i));            query[mp[b]].push_back(Query(mp[a], i));            ansQue.push_back(make_pair(mp[a], mp[b]));        }        int rt;        for (int i = 1; i <= n; i++)        {            if (!inDegree[i])            {                rt = i;                break;            }        }        lca(rt, 0);        for (int i = 0; i < m; i++)        {            int fr = ansQue[i].first;            int to = ansQue[i].second;            if (fr == to)            {                printf("0\n");            }            else if (fr == ans[i])            {                printf("1\n");            }            else if (to == ans[i])            {                printf("%d\n", step[fr] - step[to]);            }            else            {                printf("%d\n", step[fr] - step[ans[i]] + 1);            }        }    }    return 0;}

wa tarjan离线：

#include <iostream>#include <cstdio>#include <cstdlib>#include <algorithm>#include <cstring>#include <cmath>#include <stack>#include <vector>#include <queue>#include <map>#include <set>#include <climits>#include <cassert>#define Min(a,b) ((a)<(b)?(a):(b))#define Max(a,b) ((a)>(b)?(a):(b))#define LL long long#define lson lo, mi, rt << 1#define rson mi + 1, hi, rt << 1 | 1using namespace std;const int maxn = 100000 + 10;const int inf = 0x3f3f3f3f;const double eps = 1e-8;const double pi = acos(-1.0);const double ee = exp(1.0);map<string, int> mp;vector<int> ans;vector<pair<int, int> > ansQue;int step[maxn];int n;vector<int> edge[maxn], query[maxn];int inDegree[maxn];int ancestor[maxn];bool vis[maxn];int fa[maxn];int Rank[maxn];void Init(int n){    mp.clear();    ans.clear();    ansQue.clear();    for (int i = 1; i <= n; i++)    {        fa[i] = i;        Rank[i] = 0;        edge[i].clear();        query[i].clear();    }    memset(vis, false, sizeof(vis));    memset(inDegree, 0, sizeof(inDegree));    memset(ancestor, 0, sizeof(ancestor));    memset(step, 0, sizeof(step));}int Find(int x){    if (fa[x] != x)        fa[x] = Find(fa[x]);    return fa[x];}void Union(int u, int v){    int fau = Find(u);    int fav = Find(v);    if (fau == fav)        return;    if (Rank[fau] < Rank[fav])    {        fa[fau] = fav;    }    else    {        fa[fav] = fau;        if (Rank[fau] == Rank[fav])            Rank[fau]++;    }}void lca(int rt, int num){    //自成集合    step[rt] = num;    ancestor[rt] = rt;    int sz = edge[rt].size();    for (int i = 0; i < sz; i++)    {        int v = edge[rt][i];        lca(v, num + 1);                     //递归子树        Union(rt, v);               //合并子树与根        ancestor[Find(v)] = rt;          //子树祖先也指向根    }    vis[rt] = true;    sz = query[rt].size();    for (int i = 0; i < sz; i++)    {        if (vis[query[rt][i]])        {            int v = query[rt][i];            ans.push_back(ancestor[Find(v)]);        }    }    return;}void bfs(int rt){    memset(step, -1, sizeof(step));    step[rt] = 1;    queue<int> q;    q.push(rt);    while (!q.empty())    {        int now = q.front();        q.pop();        int sz = edge[now].size();        for (int i = 0; i < sz; i++)        {            int v = edge[now][i];            if (step[v] == -1)            {                step[v] = step[now] + 1;                q.push(v);            }        }    }}int main(){#ifdef LOCAL    freopen("in.txt", "r", stdin);#endif // LOCAL    int ncase;    scanf("%d", &ncase);    while (ncase--)    {        int n, m;        scanf("%d%d", &n, &m);        Init(n);        int tot = 1;        for (int i = 1; i < n; i++)        {            string a, b;            cin >> a >> b;            if (mp.find(a) == mp.end())            {                mp[a] = tot++;            }            if (mp.find(b) == mp.end())            {                mp[b] = tot++;            }            edge[mp[b]].push_back(mp[a]);            inDegree[mp[a]]++;        }        for (int i = 0; i < m; i++)        {            string a, b;            cin >> a >> b;            query[mp[a]].push_back(mp[b]);            query[mp[b]].push_back(mp[a]);            ansQue.push_back(make_pair(mp[a], mp[b]));        }//        if (n == 1)//        {//            for (int i = 0; i < m; i++)//            {//                printf("0\n");//            }//            continue;//        }        int rt;        for (int i = 1; i <= n; i++)        {            if (!inDegree[i])            {                rt = i;                break;            }        }//        bfs(rt);        lca(rt, 0);        for (int i = 0; i < m; i++)        {            int fr = ansQue[i].first;            int to = ansQue[i].second;            if (fr == to)            {                printf("0\n");            }            else if (fr == ans[i])            {                printf("1\n");            }            else if (to == ans[i])            {                printf("%d\n", step[fr] - step[to]);            }            else            {                printf("%d\n", step[fr] - step[ans[i]] + 1);            }        }    }    return 0;}

wa st在线：

#include <iostream>#include <cstdio>#include <cstdlib>#include <algorithm>#include <cstring>#include <cmath>#include <stack>#include <vector>#include <queue>#include <map>#include <set>#include <climits>#include <cassert>#define Min(a,b) ((a)<(b)?(a):(b))#define Max(a,b) ((a)>(b)?(a):(b))#define LL long long#define lson lo, mi, rt << 1#define rson mi + 1, hi, rt << 1 | 1using namespace std;const int maxn = 100000 + 10;const int inf = 0x3f3f3f3f;const double eps = 1e-8;const double pi = acos(-1.0);const double ee = exp(1.0);map<string, int> mp;int ind[maxn];int head[maxn];int edgeNum;struct Edge{    int fr, to, next;    int val;} e[maxn << 1];void initEdge(){    memset(head, -1, sizeof(head));    edgeNum = 0;}void addEdge(int fr, int to, int val){    e[edgeNum].fr = fr;    e[edgeNum].to = to;    e[edgeNum].val = val;    e[edgeNum].next = head[fr];    head[fr] = edgeNum++;    e[edgeNum].fr = to;    e[edgeNum].to = fr;    e[edgeNum].val = val;    e[edgeNum].next = head[to];    head[to] = edgeNum++;}bool vis[maxn];int dis[maxn];          //根节点到当前点的距离int ver[maxn << 1];     //dfs遍历时节点的编号int dep[maxn << 1];     //dfs遍历时节点的深度int R[maxn];            //dfs遍历时第一次出现当前节点时的遍历序号int tot;                //下标计数器void dfs(int u, int d){    vis[u] = true;    ver[++tot] = u;    R[u] = tot;    dep[tot] = d;    for (int i = head[u]; i != -1; i = e[i].next)    {        if (!vis[e[i].to])        {            int v = e[i].to;            int val = e[i].val;            dis[v] = dis[u] + val;            dfs(v, d + 1);            ver[++tot] = u;            dep[tot] = d;        }    }}//ST算法中保存的是当前段深度最小的节点的序号int minDepVerIndex[maxn << 1][10];// n = (n * 2 - 1)void queryInit(int n){    ////////////////////////////    for (int i = 1; i <= n; i++)    {        minDepVerIndex[i][0] = i;    }    ////////////////////////////    for (int j = 1; (1 << j) <= n; j++)    {        for (int i = 1; i + (1 << j) - 1 <= n; i++)        {            int p = (1 << (j - 1));            int u = minDepVerIndex[i][j - 1];            int v = minDepVerIndex[i + p][j - 1];            minDepVerIndex[i][j] = dep[u] < dep[v] ? u : v;        }    }}int queryMin(int l, int r){    int k = log2((double)(r - l + 1));    int u = minDepVerIndex[l][k];    int v = minDepVerIndex[r - (1 << k) + 1][k];    return dep[u] < dep[v] ? u : v;}int lca(int u, int v){    int l = R[u];    int r = R[v];    if (l > r)        swap(l, r);    int index = queryMin(l, r);    return ver[index];}int main(){#ifdef LOCAL    freopen("in.txt", "r", stdin);#endif // LOCAL    int ncase;    scanf("%d", &ncase);    while (ncase--)    {        int n, m;        scanf("%d%d", &n, &m);        tot = 1;        initEdge();        mp.clear();        memset(ind, 0, sizeof(ind));        for (int i = 1; i < n; i++)        {            string a, b;            cin >> a >> b;            if (mp.find(a) == mp.end())            {                mp[a] = tot++;            }            if (mp.find(b) == mp.end())            {                mp[b] = tot++;            }            addEdge(mp[a], mp[b], 1);            ind[mp[a]]++;        }        int rt;        for (int i = 1; i <= n; i++)        {            if (!ind[i])            {                rt = i;                break;            }        }        memset(vis, false, sizeof(vis));        tot = 0;        dis[1] = 0;        dfs(rt, 1);        queryInit((n << 1) - 1);        for (int i = 0; i < m; i++)        {            string a, b;            cin >> a >> b;            int fr = mp[a];            int to = mp[b];            int rt = lca(mp[a], mp[b]);//            cout << rt << endl;            if (fr == to)                puts("0");            else if (fr == rt)                puts("1");            else if (to == rt)                printf("%d\n", dis[fr] - dis[rt]);            else                printf("%d\n", dis[fr] - dis[rt] + 1);        }    }    return 0;}