【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 20
int 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;
}