[hdu5164]ac自动机

中文题目:http://bestcoder.hdu.edu.cn/contests/contest_chineseproblem.php?cid=563&pid=1003

首先贴一下bc的题解:

首先我们考虑m=1的情况。给定两个数组A={a1,a2,,an}B={b1,b2,,bk},问BA中出现了几次。令ci=ai+1ai,1i<n,同样令di=bi+1bi,1i<k,那么上述问题可以转化为cidi的模式匹配问题,这个正确性显然,也没有什么好证明的。于是对于m=1的情况只有用个kmp即可搞定。

现在考虑m>1的情况,我们考虑用ac自动机来做。考虑到字符集并不是普通的数字,而是一个分数,我们不放搞个分数类,然后用map存转移边。用m个模式串(Bob的序列)建好自动机之后,把文本串(Alice的序列)在自动机上跑一遍即可统计出答案。

 事实上,这个题的精华就在于序列变换,将问题转化为多模板匹配问题。而且由于转化后的序列有二维状态,可以用map映射重新为状态分配一个值(类似离散)。另外由于字符集比较大,所以ac自动机里面需要一点小小的修改,原来的二维数组的第二维需用map,另外需要同时记录所有儿子的字符值。原来的模板只需要小改就可以适应这种情况了。详见代码:

  1 #pragma comment(linker, "/STACK:10240000,10240000")
  2 
  3 #include <iostream>
  4 #include <cstdio>
  5 #include <algorithm>
  6 #include <cstdlib>
  7 #include <cstring>
  8 #include <map>
  9 #include <queue>
 10 #include <deque>
 11 #include <cmath>
 12 #include <vector>
 13 #include <ctime>
 14 #include <cctype>
 15 #include <set>
 16 #include <bitset>
 17 #include <functional>
 18 #include <numeric>
 19 #include <stdexcept>
 20 #include <utility>
 21 
 22 using namespace std;
 23 
 24 #define mem0(a) memset(a, 0, sizeof(a))
 25 #define mem_1(a) memset(a, -1, sizeof(a))
 26 #define lson l, m, rt << 1
 27 #define rson m + 1, r, rt << 1 | 1
 28 #define define_m int m = (l + r) >> 1
 29 #define rep_up0(a, b) for (int a = 0; a < (b); a++)
 30 #define rep_up1(a, b) for (int a = 1; a <= (b); a++)
 31 #define rep_down0(a, b) for (int a = b - 1; a >= 0; a--)
 32 #define rep_down1(a, b) for (int a = b; a > 0; a--)
 33 #define all(a) (a).begin(), (a).end()
 34 #define lowbit(x) ((x) & (-(x)))
 35 #define constructInt4(name, a, b, c, d) name(int a = 0, int b = 0, int c = 0, int d = 0): a(a), b(b), c(c), d(d) {}
 36 #define constructInt3(name, a, b, c) name(int a = 0, int b = 0, int c = 0): a(a), b(b), c(c) {}
 37 #define constructInt2(name, a, b) name(int a = 0, int b = 0): a(a), b(b) {}
 38 #define pchr(a) putchar(a)
 39 #define pstr(a) printf("%s", a)
 40 #define sstr(a) scanf("%s", a)
 41 #define sint(a) scanf("%d", &a)
 42 #define sint2(a, b) scanf("%d%d", &a, &b)
 43 #define sint3(a, b, c) scanf("%d%d%d", &a, &b, &c)
 44 #define pint(a) printf("%d
", a)
 45 #define test_print1(a) cout << "var1 = " << a << endl
 46 #define test_print2(a, b) cout << "var1 = " << a << ", var2 = " << b << endl
 47 #define test_print3(a, b, c) cout << "var1 = " << a << ", var2 = " << b << ", var3 = " << c << endl
 48 
 49 typedef long long LL;
 50 typedef pair<int, int> pii;
 51 typedef vector<int> vi;
 52 
 53 const int dx[8] = {0, 0, -1, 1, 1, 1, -1, -1};
 54 const int dy[8] = {-1, 1, 0, 0, 1, -1, 1, -1 };
 55 const int maxn = 3e4 + 7;
 56 const int md = 10007;
 57 const int inf = 1e9 + 7;
 58 const LL inf_L = 1e18 + 7;
 59 const double pi = acos(-1.0);
 60 const double eps = 1e-6;
 61 
 62 template<class T>T gcd(T a, T b){return b==0?a:gcd(b,a%b);}
 63 template<class T>bool max_update(T &a,const T &b){if(b>a){a = b; return true;}return false;}
 64 template<class T>bool min_update(T &a,const T &b){if(b<a){a = b; return true;}return false;}
 65 template<class T>T condition(bool f, T a, T b){return f?a:b;}
 66 template<class T>void copy_arr(T a[], T b[], int n){rep_up0(i,n)a[i]=b[i];}
 67 int make_id(int x, int y, int n) { return x * n + y; }
 68 
 69 LL ans;
 70 
 71 struct AhoCorasickAutoMata {
 72     const static int maxn = 250007;
 73     int cc;
 74     map<int, int> ch[maxn];
 75     vector<int> son[maxn];
 76     int val[maxn], last[maxn], f[maxn];
 77 
 78     void clear() { cc = 0; mem0(val); mem0(ch); mem0(last); mem0(f); rep_up0(i, maxn) { son[i].clear(); ch[i].clear(); } }
 79 
 80     void Insert(int s[], int n) {
 81         int pos = 0;
 82         rep_up0(i, n) {
 83             int id = s[i];
 84             if(!ch[pos][id]) {
 85                 ch[pos][id] = ++ cc;
 86                 son[pos].push_back(id);
 87             }
 88             pos = ch[pos][id];
 89         }
 90         val[pos] ++;
 91     }
 92 
 93     void print(int j) {
 94         if (j) {
 95             ans += val[j];
 96             print(last[j]);
 97         }
 98     }
 99 
100     void find(int T[], int n) {
101         int j = 0;
102         rep_up0(i, n) {
103             int c = T[i];
104             while (j && !ch[j][c]) j = f[j];
105             j = ch[j][c];
106             if (val[j]) print(j);
107             else {
108                 if (last[j]) print(last[j]);
109             }
110         }
111     }
112 
113     int getFail() {
114         queue<int> q;
115         f[0] = 0;
116         int SZ = son[0].size();
117         rep_up0(i, SZ) {
118             int c = son[0][i];
119             int u = ch[0][c];
120             q.push(u);
121         }
122         while (!q.empty()) {
123             int r = q.front(), SZ = son[r].size(); q.pop();
124             rep_up0(i, SZ) {
125                 int c = son[r][i];
126                 int u = ch[r][c];
127                 q.push(u);
128                 int v = f[r];
129                 while (v && !ch[v][c]) v = f[v];
130                 f[u] = ch[v][c];
131                 last[u] = val[f[u]]? f[u] : last[f[u]];
132             }
133         }
134     }
135 };
136 
137 AhoCorasickAutoMata ac;
138 map<pii, int> mp;
139 int pa[100007], pb[100007];
140 int a[100007], b[300007];
141 
142 int main() {
143     //freopen("in.txt", "r", stdin);
144     int T, n, m, tot = 0;
145     cin >> T;
146     while (T--) {
147         ans = 0;
148         ac.clear();
149         mp.clear();
150         cin >> n >> m;
151         rep_up0(i, n) {
152             sint(a[i]);
153         }
154         rep_up0(i, n - 1) {
155             int g = gcd(a[i], a[i + 1]);
156             int ga = a[i] / g, gb = a[i + 1] / g;
157             int &x = mp[make_pair(ga, gb)];
158             if (!x) x = ++ tot;
159             pa[i] = x;
160         }
161 
162         rep_up0(i, m) {
163             int k;
164             sint(k);
165             rep_up0(j, k) {
166                 sint(b[j]);
167             }
168             if (k > n) continue;
169             if (k == 1) {
170                 ans += n;
171                 continue;
172             }
173             rep_up0(j, k - 1) {
174                 int g = gcd(b[j], b[j + 1]);
175                 int ga = b[j] / g, gb = b[j + 1] / g;
176                 int &x = mp[make_pair(ga, gb)];
177                 if (!x) x = ++ tot;
178                 pb[j] = x;
179             }
180             ac.Insert(pb, k - 1);
181         }
182         ac.getFail();
183         ac.find(pa, n - 1);
184         cout << ans << endl;
185     }
186     return 0;
187 }
View Code
原文地址:https://www.cnblogs.com/jklongint/p/4471504.html