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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.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.
You should output a number on a separate line,which indicates the number of valid shifts for the given text T and pattern P.
abababab abab
3
思路：
简单的计数题。
代码：
#include#include #define N 1000000 int main(void){ int tlen, plen, i; char t[N+1], p[N+1]; while (scanf("%s%s", t, p) != EOF) { tlen = strlen(t); plen = strlen(p); int count = 0; for(i=0; i<=tlen-plen; i++) { if (t[i] == p[0] && strncmp(t+i, p, plen) == 0) count ++; } printf("%d\n", count); } return 0;}/************************************************************** Problem: 1094 User: liangrx06 Language: C Result: Accepted Time:30 ms Memory:2788 kb****************************************************************/
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