【数据结构基础】串的模式匹配-BF算法

#include<stdio.h>#pragma warning(disable:4996)//兼容vs中使用scanf#define Maxsize 20int StrIndex_BF(char *s, char *t) {    int i = 1, j = 1;    while (i <= s[0] && j <= t[0]) {        if (s[i] == t[j]) {            i++;            j++;        }        else {            i = i - j + 2;//回溯             j = 1;        }    }    if (j == t[0]+ 1) {        return (i - t[0]);    }    else {        return -1;    }}char* ReadStr(char *s1) {    int i, length;    scanf("%d\n", &length);    s1[0] = length;    for (i = 1; i <= s1[0]; i++) {        s1[i] = getchar();    }    s1[i] = '\0';    return s1;}int main(void) {    char Str1[Maxsize], Str2[Maxsize], *p, *q;    int index;    p = ReadStr(Str1);    q = ReadStr(Str2);    index = StrIndex_BF(p, q);    if (index == -1) {        printf("Not Find");    }    else {        printf("%d\n", index);    }    return 0;}