• Cyclical Quest CodeForces


    题意:

    给出一个字符串,给出一些子串,问每个子串分别在母串中圆环匹配的次数,

    圆环匹配的意思是将该子串拆成两段再首位交换相接的串和母串匹配,比

    如aaab变成baaa,abaa,aaba再进行匹配。

     题解:

     如何求出所有的循环串出现的次数呢?

    先将S串放入后缀自动机

    把查询串扩大一倍,然后在后缀自动机上去匹配,

    只要匹配长度大于子串长度小于2倍子串长度的,必然对应这一种循环串

    记录一下

    // 每个节点子串出现的次数

    统计答案即可

      1 #include <set>
      2 #include <map>
      3 #include <stack>
      4 #include <queue>
      5 #include <cmath>
      6 #include <ctime>
      7 #include <cstdio>
      8 #include <string>
      9 #include <vector>
     10 #include <cstring>
     11 #include <iostream>
     12 #include <algorithm>
     13 #include <unordered_map>
     14 
     15 #define  pi    acos(-1.0)
     16 #define  eps   1e-9
     17 #define  fi    first
     18 #define  se    second
     19 #define  rtl   rt<<1
     20 #define  rtr   rt<<1|1
     21 #define  bug                printf("******
    ")
     22 #define  mem(a, b)          memset(a,b,sizeof(a))
     23 #define  name2str(x)        #x
     24 #define  fuck(x)            cout<<#x" = "<<x<<endl
     25 #define  sfi(a)             scanf("%d", &a)
     26 #define  sffi(a, b)         scanf("%d %d", &a, &b)
     27 #define  sfffi(a, b, c)     scanf("%d %d %d", &a, &b, &c)
     28 #define  sffffi(a, b, c, d) scanf("%d %d %d %d", &a, &b, &c, &d)
     29 #define  sfL(a)             scanf("%lld", &a)
     30 #define  sffL(a, b)         scanf("%lld %lld", &a, &b)
     31 #define  sfffL(a, b, c)     scanf("%lld %lld %lld", &a, &b, &c)
     32 #define  sffffL(a, b, c, d) scanf("%lld %lld %lld %lld", &a, &b, &c, &d)
     33 #define  sfs(a)             scanf("%s", a)
     34 #define  sffs(a, b)         scanf("%s %s", a, b)
     35 #define  sfffs(a, b, c)     scanf("%s %s %s", a, b, c)
     36 #define  sffffs(a, b, c, d) scanf("%s %s %s %s", a, b,c, d)
     37 #define  FIN                freopen("../in.txt","r",stdin)
     38 #define  gcd(a, b)          __gcd(a,b)
     39 #define  lowbit(x)          x&-x
     40 #define  IO                 iOS::sync_with_stdio(false)
     41 
     42 
     43 using namespace std;
     44 typedef long long LL;
     45 typedef unsigned long long ULL;
     46 const ULL seed = 13331;
     47 const LL INFLL = 0x3f3f3f3f3f3f3f3fLL;
     48 const int maxm = 8e6 + 10;
     49 const int INF = 0x3f3f3f3f;
     50 const int mod = 1e9 + 7;
     51 const int maxn = 250007;
     52 char s[maxn];
     53 int Q;
     54 
     55 struct Suffix_Automaton {
     56     int last, tot, nxt[maxn << 1][26], fail[maxn << 1];//last是未加入此字符前最长的前缀(整个串)所属的节点的编号
     57     int len[maxn << 1];// 最长子串的长度 (该节点子串数量 = len[x] - len[fa[x]])
     58     int sa[maxn << 1], c[maxn << 1];
     59     int sz[maxn << 1];// 被后缀链接的个数,方便求节点字符串的个数
     60     LL num[maxn << 1];// 该状态子串的数量
     61     LL maxx[maxn << 1];// 长度为x的子串出现次数最多的子串的数目
     62     LL sum[maxn << 1];// 该节点后面所形成的自字符串的总数
     63     LL subnum, sublen;// subnum表示不同字符串数目,sublen表示不同字符串总长度
     64     int X[maxn << 1], Y[maxn << 1]; // Y表示排名为x的节点,X表示该长度前面还有多少个
     65     int minn[maxn << 1], mx[maxn << 1];//minn[i]表示多个串在后缀自动机i节点最长公共子串,mx[i]表示单个串的最长公共子串
     66     void init() {
     67         tot = last = 1;
     68         fail[1] = len[1] = 0;
     69         for (int i = 0; i < 26; i++) nxt[1][i] = 0;
     70     }
     71 
     72     void extend(int c) {
     73         int u = ++tot, v = last;
     74         len[u] = len[v] + 1;
     75         num[u] = 1;
     76         for (; v && !nxt[v][c]; v = fail[v]) nxt[v][c] = u;
     77         if (!v) fail[u] = 1, sz[1]++;
     78         else if (len[nxt[v][c]] == len[v] + 1) fail[u] = nxt[v][c], sz[nxt[v][c]]++;
     79         else {
     80             int now = ++tot, cur = nxt[v][c];
     81             len[now] = len[v] + 1;
     82             memcpy(nxt[now], nxt[cur], sizeof(nxt[cur]));
     83             fail[now] = fail[cur];
     84             fail[cur] = fail[u] = now;
     85             for (; v && nxt[v][c] == cur; v = fail[v]) nxt[v][c] = now;
     86             sz[now] += 2;
     87         }
     88         last = u;
     89         //return len[last] - len[fail[last]];//多添加一个子串所产生不同子串的个数
     90     }
     91 
     92     void get_num() {// 每个节点子串出现的次数
     93         for (int i = 1; i <= tot; i++) X[len[i]]++;
     94         for (int i = 1; i <= tot; i++) X[i] += X[i - 1];
     95         for (int i = 1; i <= tot; i++) Y[X[len[i]]--] = i;
     96         for (int i = tot; i >= 1; i--) num[fail[Y[i]]] += num[Y[i]];
     97     }
     98 
     99     void get_maxx(int n) {// 长度为x的子串出现次数最多的子串的数目
    100         get_num();
    101         for (int i = 1; i <= tot; i++) maxx[len[i]] = max(maxx[len[i]], num[i]);
    102     }
    103 
    104     void get_sum() {// 该节点后面所形成的自字符串的总数
    105         get_num();
    106         for (int i = tot; i >= 1; i--) {
    107             sum[Y[i]] = 1;
    108             for (int j = 0; j <= 25; j++)
    109                 sum[Y[i]] += sum[nxt[Y[i]][j]];
    110         }
    111     }
    112 
    113     void get_subnum() {//本质不同的子串的个数
    114         subnum = 0;
    115         for (int i = 1; i <= tot; i++) subnum += len[i] - len[fail[i]];
    116     }
    117 
    118     void get_sublen() {//本质不同的子串的总长度
    119         sublen = 0;
    120         for (int i = 1; i <= tot; i++) sublen += 1LL * (len[i] + len[fail[i]] + 1) * (len[i] - len[fail[i]]) / 2;
    121     }
    122 
    123     void get_sa() { //获取sa数组
    124         for (int i = 1; i <= tot; i++) c[len[i]]++;
    125         for (int i = 1; i <= tot; i++) c[i] += c[i - 1];
    126         for (int i = tot; i >= 1; i--) sa[c[len[i]]--] = i;
    127     }
    128 
    129     void match(char s[]) {//多个串的最长公共子串
    130         mem(mx, 0);
    131         int n = strlen(s), p = 1, maxlen = 0;
    132         for (int i = 0; i < n; i++) {
    133             int c = s[i] - 'a';
    134             if (nxt[p][c]) p = nxt[p][c], maxlen++;
    135             else {
    136                 for (; p && !nxt[p][c]; p = fail[p]);
    137                 if (!p) p = 1, maxlen = 0;
    138                 else maxlen = len[p] + 1, p = nxt[p][c];
    139             }
    140             mx[p] = max(mx[p], maxlen);
    141         }
    142         for (int i = tot; i; i--)
    143             mx[fail[i]] = max(mx[fail[i]], min(len[fail[i]], mx[i]));
    144         for (int i = tot; i; i--)
    145             if (minn[i] == -1 || minn[i] > maxx[i]) minn[i] = mx[i];
    146     }
    147 
    148     void get_kth(int k) {//求出字典序第K的子串
    149         int pos = 1, cnt;
    150         string s = "";
    151         while (k) {
    152             for (int i = 0; i <= 25; i++) {
    153                 if (nxt[pos][i] && k) {
    154                     cnt = nxt[pos][i];
    155                     if (sum[cnt] < k) k -= sum[cnt];
    156                     else {
    157                         k--;
    158                         pos = cnt;
    159                         s += (char) (i + 'a');
    160                         break;
    161                     }
    162                 }
    163             }
    164         }
    165         cout << s << endl;
    166     }
    167 
    168     int vis[maxn << 1];
    169 
    170     void solve(int lenlen, int id) {
    171         int maxlen = 0, p = 1, ans = 0;
    172         for (int i = 1; i <= lenlen * 2; i++) {
    173             int c = s[i] - 'a';
    174             if (nxt[p][c]) maxlen++, p = nxt[p][c];
    175             else {
    176                 for (; p && !nxt[p][c]; p = fail[p]);
    177                 if (p == 0) p = 1, maxlen = 0;
    178                 else maxlen = len[p] + 1, p = nxt[p][c];
    179             }
    180             if (i >= lenlen && maxlen >= lenlen) {
    181                 int temp = p;
    182                 while (temp && !(len[fail[temp]] + 1 <= lenlen && len[temp] >= lenlen))temp = fail[temp];
    183                 if (!temp) temp = 1;
    184                 if (vis[temp] != id) vis[temp] = id, ans += num[temp];
    185             }
    186         }
    187         printf("%d
    ", ans);
    188     }
    189 } sam;
    190 
    191 int main() {
    192 #ifndef ONLINE_JUDGE
    193     FIN;
    194 #endif
    195     sam.init();
    196     sfs(s + 1);
    197     int n = strlen(s + 1);
    198     for (int i = 1; i <= n; i++) sam.extend((s[i] - 'a'));
    199     sam.get_num();
    200     sfi(Q);
    201     for (int i = 1; i <= Q; i++) {
    202         sfs(s + 1);
    203         int len = strlen(s + 1);
    204         for (int i = 1; i <= len; i++) s[i + len] = s[i];
    205         s[2 * len + 1] = '';
    206         //fuck(s + 1);
    207         sam.solve(len, i);
    208     }
    209 #ifndef ONLINE_JUDGE
    210     cout << "Totle Time : " << (double) clock() / CLOCKS_PER_SEC << "s" << endl;
    211 #endif
    212     return 0;
    213 }
    View Code
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  • 原文地址:https://www.cnblogs.com/qldabiaoge/p/11553763.html
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