九度oj-1094-String Matching

时间限制：1 秒

内存限制：32 兆

特殊判题：否

提交：1263

解决：689

题目描述：

    Finding all occurrences of a pattern in a text is a problem that arises frequently in text-editing programs. 

    Typically,the text is a document being edited,and the pattern searched for is a particular word supplied by the user.  

    We assume that the text is an array T[1..n] of length n and that the pattern is an array P[1..m] of length m<=n.We further assume that the elements of P and  T are all alphabets(∑={a,b...,z}).The character arrays P and T are often called strings of characters.  

    We say that pattern P occurs with shift s in the text T if 0<=s<=n and T[s+1..s+m] = P[1..m](that is if T[s+j]=P[j],for 1<=j<=m).  

    If P occurs with shift s in T,then we call s a valid shift;otherwise,we calls a invalid shift. 

    Your task is to calculate the number of vald shifts for the given text T and p attern P.

输入：

   For each case, there are two strings T and P on a line,separated by a single space.You may assume both the length of T and P will not exceed 10^6. 

输出：

    You should output a number on a separate line,which indicates the number of valid shifts for the given text T and pattern P.

样例输入：

abababab abab

样例输出：

3

来源：2006年上海交通大学计算机研究生机试真题

#include<stdio.h>
#include<string.h>
char a[1000005],b[1000005];
int main()
{
int na,nb,i,j;
while(scanf("%s%s",a,b)!=EOF)
{
int count=0;
na=strlen(a);
nb=strlen(b);
for(i=0;i<=na-nb;i++)
{
for(j=0;j<nb;j++)
if(a[i+j]!=b[j])
break;
if(j==nb)
count++;
}
printf("%d\n",count);
}
return 0;
}