c语言sunday算法代码

以下是C语言实现的Sunday算法代码：

#include <stdio.h>
#include <string.h>

#define MAX_LEN 1000

int sunday(char* str, char* pattern) {
    int len_str = strlen(str);
    int len_pattern = strlen(pattern);
    int jump[256];
    for (int i = 0; i < 256; i++) {
        jump[i] = len_pattern + 1;
    }
    for (int i = 0; i < len_pattern; i++) {
        jump[pattern[i]] = len_pattern - i;
    }
    int i = 0;
    while (i <= len_str - len_pattern) {
        int j = 0;
        while (j < len_pattern && str[i + j] == pattern[j]) {
            j++;
        }
        if (j == len_pattern) {
            return i;
        }
        i += jump[str[i + len_pattern]];
    }
    return -1;
}

int main() {
    char str[MAX_LEN];
    char pattern[MAX_LEN];
    printf("请输入字符串：");
    scanf("%s", str);
    printf("请输入模式串：");
    scanf("%s", pattern);
    int pos = sunday(str, pattern);
    if (pos == -1) {
        printf("未找到匹配的子串\n");
    } else {
        printf("匹配的子串位置为：%d\n", pos);
    }
    return 0;
}