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：1098

解决：587

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

#include<stdio.h>
#include<string.h>
char s1[1000001];
char s2[1000001];
int main(int argc, char *argv[])
{
    while(~scanf("%s%s",s1,s2))
    {
        int cnt=0;
        int i=0;
        char *s=s1;
        while(s=strstr(s,s2))
        {
            s++;
            cnt++;
        }
        printf("%d\n",cnt);
    }

    return 0;
}

/**************************************************************
    Problem: 1094
    User: kirchhoff
    Language: C
    Result: Accepted
    Time:20 ms
    Memory:2868 kb
****************************************************************/