Bzoj4598: [Sdoi2016]模式字符串 点分治 哈希

 1 #pragma GCC optimize(2)
 2 #include<cstdio>
 3 #include<cstring>
 4 #include<algorithm>
 5 #include<cctype>
 6 #include<iostream>
 7 #define debug cerr
 8 using namespace std;
 9 typedef unsigned long long int ulli;
10 using std::max;using std::reverse;
11 const int maxn=1e6+1e2;
12 const ulli base = 31;
13 const int inf=0x3f3f3f3f;
14 
15 char in[maxn],tar[maxn]; // input string and target string .
16 ulli pows[maxn],hpr[maxn],hsu[maxn]; // hash prefix and hash suffix .
17 int s[maxn],t[maxn<<1],nxt[maxn<<1],ban[maxn],cnt;
18 int dep[maxn],siz[maxn],mxs[maxn],prf[maxn],suf[maxn],sprf[maxn],ssuf[maxn]; // mxs[0] = inf  , paired prf[length] .
19 int n,m;
20 ulli ans;
21 
22 bool vis[maxn];
23 
24 inline void addedge(int from,int to) {
25     t[++cnt] = to , nxt[cnt] = s[from] ,s[from] = cnt;
26 }
27 inline void findroot(int pos,const int &fa,const int &fs,int &rt) {
28     siz[pos] = 1 , mxs[pos] = 0;
29     for(int at=s[pos];at;at=nxt[at]) if( t[at] != fa && !ban[t[at]] ) {
30         findroot(t[at],pos,fs,rt) , siz[pos] += siz[t[at]] , mxs[pos] = max( mxs[pos] , siz[t[at]] );
31     }
32     if( ( mxs[pos] = max( mxs[pos] , fs - siz[pos] ) ) <= mxs[rt] ) rt = pos;
33 }
34 inline void dfs(int pos,int fa,int dep,int &mxd,const char &mid,ulli h) {
35     mxd = max( mxd , dep ) , h += in[pos] * pows[dep-1]; // add in[pos] to first char .
36     if( h == hpr[dep] ) {
37         ++prf[dep%m];
38         if( mid == tar[dep%m+1] ) ans += ssuf[m-dep%m-1];
39     }
40     if( h == hsu[dep] ) {
41         ++suf[dep%m];
42         if( mid == tar[m-dep%m] ) ans += sprf[m-dep%m-1];
43     }
44     for(int at=s[pos];at;at=nxt[at]) if( t[at] != fa && !ban[t[at]] ) dfs(t[at],pos,dep+1,mxd,mid,h);
45 }
46 inline void solve(int pos,int fs) {
47     if( fs < m ) return;
48     int rt = 0 , full = 0;
49     *mxs = inf , findroot(pos,-1,fs,rt) , ban[rt] = 1;
50     if( in[rt] == tar[1] ) ++sprf[0];
51     if( in[rt] == tar[m] ) ++ssuf[0];
52     for(int at=s[rt],mxd;at;at=nxt[at]) if( !ban[t[at]] ) {
53         mxd = 0 , dfs(t[at],rt,1,mxd,in[rt],0) , full = max( full , mxd );
54         for(int i=0;i<=mxd;i++) sprf[i] += prf[i] , ssuf[i] += suf[i] , prf[i] = suf[i] = 0;
55     }
56     for(int i=0;i<=full;i++) sprf[i] = ssuf[i] = 0;
57     for(int at=s[rt];at;at=nxt[at]) if( !ban[t[at]] ) solve(t[at],siz[t[at]]<siz[rt]?siz[t[at]]:fs-siz[rt]);
58 }
59 
60 inline char nextchar() {
61     static const int BS = 1 << 21;
62     static char buf[BS],*st=buf+BS,*ed=buf+BS;
63     if( st == ed ) ed = buf + fread(st=buf,1,BS,stdin);
64     return st == ed ? -1 : *st++;
65 }
66 inline int getint() {
67     int ret = 0 , ch;
68     while( !isdigit(ch=nextchar()) );
69     do ret = ret * 10 + ch - ‘0‘; while( isdigit(ch=nextchar()) );
70     return ret;
71 }
72 inline void getstr(char* s) {
73     char ch;
74     while( !isalpha(ch=nextchar()) );
75     do *s++ = ch; while( isalpha(ch=nextchar()) );
76 }
77 inline void gethsh(ulli* dst) {
78     for(int i=m+1;i<=n;i++) tar[i] = tar[i-m];
79     for(int i=1;i<=n;i++) dst[i] = dst[i-1] * base + tar[i];
80 }
81 inline void fix(char* s,int len) {
82     for(int i=1;i<=len;i++) s[i] -= ‘A‘ - 1;
83 }
84 inline void solve_case() {
85     n = getint() , m = getint() , getstr(in+1) , fix(in,n) , memset(s,0,sizeof(s)) , memset(ban,0,sizeof(ban)) , cnt = ans = 0 , *pows = 1;
86     for(int i=1;i<=n;i++) pows[i] = pows[i-1] * base;
87     for(int i=1,a,b;i<n;i++) a = getint() , b = getint() , addedge(a,b) , addedge(b,a);
88     getstr(tar+1) , fix(tar,m) , gethsh(hpr) , reverse(tar+1,tar+1+m) , gethsh(hsu) , reverse(tar+1,tar+1+m);
89     solve(1,n) , printf("%llu\n",ans);
90 }
91 
92 int main() {
93     static int T;
94     T = getint();
95     while(T--) solve_case();
96     return 0;
97 }