微软校招编程题"Beautiful String"的状态机解法

如果一个字符串包括三组或者更多组的连续升序字母，每组长度相等，那么我们就称这个字符串是Beautiful String

如下是一些Beautiful String的例子：
abc、cde、aabbcc、aaabbbccc
这些不是Beautiful String:
abd、cba、aabbc、zab
输入一个只含有小写字母的字符串，如果它含有一个Beautiful的子串，就输出YES，否则输出NO

输入：
第一行是案例个数，之后的每一行是一个数字，一个字符串，数字表示字符串长度，长度小于10MB

输出：
YES或者NO

#include <stdio.h>
#include <stdlib.h>

int main(void)
{
    int n, length;
    char * str;
    char *p;
    char * p_bak;
    int count[3];
    char pre;
    scanf("%d", &n);
    while (n--)
    {
        scanf("%d", &length);
        str = (char*)malloc(sizeof(char) * (length + 1));
        scanf("%s", str);
        p = str;
        count[0] = 0;
        count[1] = 0;
        count[2] = 0;
        p_bak = p;
        goto SECTION_0;
    REWIND:
        count[0] = 0;
        count[1] = 0;
        count[2] = 0;
        p = ++p_bak;
        goto SECTION_0;
    SUCCESS:
        printf("YES\n");
        free(str);
        continue;
    FAIL:
        printf("NO\n");
        free(str);
        continue;
    SECTION_0:
        pre = *p;
    SECTION_A:
        if (*p == ‘\0‘)
            goto FAIL;
        if (*p == pre)
        {
            ++p;
            ++count[0];
            goto SECTION_A;
        }
        else if (*p == pre + 1)
        {
            goto SECTION_B;
        }
        else
        {
            goto REWIND;
        }
    SECTION_B:
        if (*p == ‘\0‘)
        {
            goto FAIL;
            goto FAIL; //向苹果致敬(●‘?‘●)，参见 http://coolshell.cn/articles/11112.html
        }
        if (*p == pre + 1)
        {
            ++p;
            ++count[1];
            goto SECTION_B;
        }
        else if (*p == pre + 2)
        {
            goto SECTION_C;
        }
        else
        {
            goto REWIND;
        }
    SECTION_C:
        if (count[0] != count[1])
            goto REWIND;
        if (*p == ‘\0‘)
            goto FINAL_CHECK;
        if (count[2] == count[1])
            goto SUCCESS;
        if (*p == pre + 2)
        {
            ++p;
            ++count[2];
            goto SECTION_C;
        }
    FINAL_CHECK:
        if (count[2] != count[1])
            goto REWIND;
        else
            goto SUCCESS;
    }
    return 0;
}