[BZOJ2795] [Poi2012] A horrible Poem

2795: [Poi2012]a horrible Poem time limit:50 Sec Memory limit:128 MB
submit:261 solved:150
[Submit] [Status] [Discuss] Description

A string s consisting of lowercase English letters is given, and Q is asked to answer the shortest follow-up link of a substring of s.
If string B is a looping section of string A, then a can be repeated several times by B.

Input

The first line is a positive integer n (n<=500,000), which represents the length of S.
The second row of n lowercase English letters, representing the string s.
The third line is a positive integer q (q<=2,000,000), which indicates the number of queries.
The following q lines are two positive integers a, B (1<=a<=b<=n), representing the query string s[a: b] The shortest cycle section length.

Output

Output Q-line positive integers, and the positive integers of line I correspond to the answer of the I query.

Sample Input8
Aaabcabc
3
1 3
3 8
4 8

Sample Output1
3
5HINT Source

Acknowledgement Jiangzoi&oimaster

[Submit] [Status] [Discuss]

Hash, and then there is an obvious violent practice, a single inquiry is $\sqrt n$.

Can be optimized, record the number of occurrences of each letter, the number of links must be this approximate.

Time complexity is not very good $o (n+q+q\sqrt N) $

1#include <cstdio>2#include <algorithm>3 #defineN 5000504 #definell unsigned long long5 using namespacestd;6InlineintRead ()7 {8     intx=0, f=1;CharCh=GetChar ();9      while(ch<'0'|| Ch>'9'){if(ch=='-') f=-1; ch=GetChar ();}Ten      while(ch>='0'&&ch<='9') {x=x*Ten+ch-'0'; ch=GetChar ();} One     returnx*F; A } -ll pow[n]={1},hash[n]; - intn,num[n][ -],q,st[n],top; the CharS[n]; -inline ll Gethash (intLintR) -{returnhash[r]-hash[l-1]*pow[r-l+1];} -InlineBOOLCheckintLintRintx) +{returnGethash (l+x,r) ==gethash (l,r-x);} -InlineintgcdintAintb) {returnB?GCD (b,a%b): A;} +InlineintQueryintLintR) A { at swap (l,r); -     intx=r-l+1, y=r-l+1; -      for(intI=1; i<= -; i++) -X=GCD (x,num[r][i]-num[l-1][i]); -     if(x==1)returny; -top=0; in      for(intI=1; i*i<=x;i++) -     if(! (%i)) to     { +st[++top]=y/i; -         if(Check (l,r,y/x*i)) the         returny/x*i; *     } $      while(!check (L,r,st[top])) top--;Panax Notoginseng     returnSt[top]; - } the intMain () + { Ascanf"%d\n",&n); theGets (s+1); +      for(intI=1; i<=n;i++) -hash[i]=hash[i-1]*233+S[i], $pow[i]=pow[i-1]*233; $      for(intI=1; i<=n;i++) -      for(intj=1; j<= -; j + +) -num[i][j]=num[i-1][j]+ (s[i]-'a'+1==j); theq=read (); -      while(q--) printf ("%d\n", query (read (), read () ));Wuyi}

View Code

[BZOJ2795] [Poi2012] A horrible Poem