2795: [Poi2012]a horrible Poem

2795: [Poi2012]a horrible Poem time limit:50 Sec Memory limit:128 MB
submit:484 solved:235
[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

First we can know, a length of Len's substring, its circulation section must be Len of the approximate, so just find the approximate Len, and then the hash to determine the line. But this complexity is q√n and will be tle, so consider optimization.
Consider if there is a letter K, then the number of cycles of this substring must be the approximate amount of k, we take all the K to a GCD, and then find approximate.

#include <cstdio>#include<algorithm>#include<iostream>#defineP 31#defineR Register#defineull unsigned long Longusing namespacestd;intRead () {Rintx=0;BOOLf=1; RCharCh=GetChar ();  while(ch<'0'|| Ch>'9'){if(ch=='-') f=0; ch=GetChar ();}  while(ch>='0'&&ch<='9') {x=x*Ten+ch-'0'; ch=GetChar ();} returnf?x:-x;}Const intn=5e5+Ten; ull Hash[n],Base[N];intn,m,vgcd,ans,c[n][ -];;CharS[n];voidGet_hash () {Base[0]=1;  for(intI=1; i<=n;i++) {Hash[i]=hash[i-1]*p+s[i]-'a'; Base[i]=Base[I1]*Q; }}voidCheckintXintYintt) {ull HAS1=hash[y-t]-hash[x-1]*Base[y-x+1-T]; ull HAS2=hash[y]-hash[x+t-1]*Base[y-x+1-T]; if(HAS1==HAS2) ans=min (ans,t);}intMain () {n=read (); Gets (s+1); m=read ();    Get_hash ();  for(intI=0; i<= -; i++){         for(intj=1; j<=n;j++) {C[j][i]=c[j-1][i]+ (s[j]-'a'==i); }    }     for(intI=1, x,y;i<=m;i++) {x=read (); Y=read (); ans=n;vgcd=y-x+1;  for(intj=0; j<= -; j + +) VGCD=__GCD (vgcd,c[y][j]-c[x-1][j]);  for(intj=1; j*j<=vgcd;j++){            if(VGCD%J)Continue; Check (x, Y,-x+1)/j); Check (x, Y,-x+1)/(vgcd/j)); } printf ("%d\n", ans); }    return 0;}

2795: [Poi2012]a horrible Poem