Description
The French author Georges Perec (1936–1982) once wrote a book, La disparition, without the letter 'e'. He was a member of the Oulipo group. A quote from the book:
Tout avait Pair normal, mais tout s’affirmait faux. Tout avait Fair normal, d’abord, puis surgissait l’inhumain, l’affolant. Il aurait voulu savoir où s’articulait l’association qui l’unissait au roman : stir son tapis, assaillant à tout instant son imagination, l’intuition d’un tabou, la vision d’un mal obscur, d’un quoi vacant, d’un non-dit : la vision, l’avision d’un oubli commandant tout, où s’abolissait la raison : tout avait l’air normal mais…
Perec would probably have scored high (or rather, low) in the following contest. People are asked to write a perhaps even meaningful text on some subject with as few occurrences of a given “word” as possible. Our task is to provide the jury with a program that counts these occurrences, in order to obtain a ranking of the competitors. These competitors often write very long texts with nonsense meaning; a sequence of 500,000 consecutive 'T's is not unusual. And they never use spaces.
So we want to quickly find out how often a word, i.e., a given string, occurs in a text. More formally: given the alphabet {'A', 'B', 'C', …, 'Z'} and two finite strings over that alphabet, a word W and a text T, count the number of occurrences of W in T. All the consecutive characters of W must exactly match consecutive characters of T. Occurrences may overlap.
Input
The first line of the input file contains a single number: the number of test cases to follow. Each test case has the following format:
- One line with the word W, a string over {'A', 'B', 'C', …, 'Z'}, with 1 ≤ |W| ≤ 10,000 (here |W| denotes the length of the string W).
- One line with the text T, a string over {'A', 'B', 'C', …, 'Z'}, with |W| ≤ |T| ≤ 1,000,000.
Output
For every test case in the input file, the output should contain a single number, on a single line: the number of occurrences of the word W in the text T.
Sample Input
3 BAPC BAPC AZA AZAZAZA VERDI AVERDXIVYERDIAN
Sample Output
1 3 0
昨天去做cf的时候B题写KMP的时候调了半天调不出来真是打脸……
所以现在开始疯狂刷KMP（当复习吧）
这题当模板用
#include<cstdio>
#include<iostream>
#include<cstring>
#include<cstdlib>
#include<algorithm>
#include<cmath>
#include<queue>
#include<deque>
#include<set>
#include<map>
#include<ctime>
#define LL long long
#define inf 0x7ffffff
#define pa pair<int,int>
#define pi 3.1415926535897932384626433832795028841971
using namespace std;
inline LL read()
{
LL x=0,f=1;char ch=getchar();
while(ch<'0'||ch>'9'){if(ch=='-')f=-1;ch=getchar();}
while(ch>='0'&&ch<='9'){x=x*10+ch-'0';ch=getchar();}
return x*f;
}
inline void write(LL a)
{
if (a<0){printf("-");a=-a;}
if (a>=10)write(a/10);
putchar(a%10+'0');
}
inline void writeln(LL a){write(a);printf("
");}
int next[100010];
char s[10010],p[1000010];
int ls,lp;
inline void pre()
{
memset(next,0,sizeof(next));
int j=0;
for (int i=2;i<=ls;i++)
{
while (j>0 && s[j+1]!=s[i])j=next[j];
if (s[j+1]==s[i])j++;
next[i]=j;
}
}
inline void KMP()
{
int j=0,ans=0;
for (int i=1;i<=lp;i++)
{
while (j>0 && s[j+1]!=p[i])j=next[j];
if (s[j+1]==p[i])j++;
if (j==ls)
{
ans++;
j=next[j];
}
}
printf("%d
",ans);
}
inline void work()
{
scanf("%s",s+1);
scanf("%s",p+1);
ls=strlen(s+1);lp=strlen(p+1);
pre();
KMP();
}
int main()
{
int T=read();
while (T--)work();
}