用后缀数组 求一个字符串的最长重复字串

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

void HouZhui(char *p);
int main()
{
char a[100] = "abcderabcmnpqabcdmnp";
HouZhui(a);
return 0;
}

void HouZhui(char *p)
{
void Qsort(char **p, int n);//对后缀数组排序
int FindSame(char *, char *);//
int n;
int i;
int max; //最长重复字串的长度
int count;
char *result;//结果的字符串
char **q;
char **first;
char **second;//遍历后缀数组
if(p == NULL)
return;
n = strlen(p);
q = (char **)malloc(sizeof(char *) * n);
if(q == NULL)
return;
for(i = 0; i < n; ++i)
q[i] = p+i;
Qsort(q, n);

for(i = 0; i < n; ++i)//观察排序结果
printf("%s\n", q[i]);
printf("\n");

first = q;
second = q+1;
max = 0;
count = 0;
result = *first;
while(second <= q+n-1)
{
count = FindSame(*first, *second);
if(count > max)
{
max = count;
result = *first;
}
first++;
second++;
}
while(max)
{
printf("%c", *result);
result++;
max--;
}
printf("\n");
free(q);
}

int FindSame(char *a, char *b)//寻找两个字符串的公共前缀的长度
{
int count = 0;
while(*a != '\0' && *b != '\0' && *a == *b)
{
a++;
b++;
count++;
}
return count;
}

void Qsort(char **p, int n)//对生成的后缀数组排序
{
int compare(char *a, char *b);
void swap(char **a, char **b);
int i, j;
char *temp;
if(n <= 1)
return;
j = -1;
temp = p[n/2];
swap(p+n/2, p+n-1);
for(i = 0; i < n-1; ++i)//这里不要弄错了
{
if(compare(p[i], temp))//p[i] 小于temp
{
j++;
if(j != i)
{
swap(p+i, p+j);
}
}
}
swap(p+n-1, p+j+1);
Qsort(p, j+1);
Qsort(p+j+2, n-j-2);
}

void swap(char **a, char **b)
{
char *temp;
temp = *a;
*a = *b;
*b = temp;
}

int compare(char *a, char *b)//不存在a和b长度相同的情况
{
while(*a != '\0' && *b != '\0' && *a == *b)
{
a++;
b++;
}
if((*a == '\0') || *a < *b)
return 1;
else
return 0;
}