字符串中的最长重复字串

/* 求一个字符串中的最长重复字串 基本思路是利用next数组来实现

next数组的定义 就是 字符串中第J个字符 必有next[J] - 1个重复

字串， 事实上 KMP查找 求模式串next数组 就是指求出模式串J个

字符前 最大的重复子串

*/

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <malloc.h>

#define __in

#define __out

#define __in__out

#define __DEBUG__XU

typedef struct __MAX_SUB

{

int start;

int len;

int tempstart;

int templen;

}MAX_SUB, *PMAX_SUB;

int GetNext(__out int *next, __in char *substring);

int main(int argc, char **argv)

{

char *string = "ccccabababab";

char *substring;

unsigned int len, sublen;

int *next;

int i;

int flag = 0;

#ifdef __DEBUG__XU

int j;

#endif

MAX_SUB maxsub = {0};

len = strlen(string);

for(i = 1; i < len; i++)

{

if(string[i] != string[0])

{

flag = 1;

break;

}

}

if(!flag)

{

printf("string has only one sort of char/n");

printf("%s", string);

return 0;

}

for(i = 0; i < len; i++)

{

#ifdef __DEBUG__XU

printf("substring first pos: %d/n", i);

#endif

substring = string + i;

sublen = strlen(substring);

next = (int *)malloc(sizeof(int) * (sublen + 1));

maxsub.templen = GetNext(next, substring);

maxsub.tempstart = i;

if(maxsub.templen > maxsub.len)

{

maxsub.len = maxsub.templen;

maxsub.start = maxsub.tempstart;

}

#ifdef __DEBUG__XU

for(j = maxsub.start; j < maxsub.len + maxsub.start; j++)

{

printf("%c", string[j]);

}

printf("/n");

#endif

free(next);

}

}

int GetNext(__out int *next, __in char *substring)

{

char *string;

int k, i;

int max_k;

string = substring;

next[0] = -1;

k = next[0];

i = 0;

max_k = k;

while(i < strlen(substring))

{

if(i + 1 == strlen(substring) )

{

if(substring[k] == substring[i])

goto kmp;

}

if(-1 == k || substring[k] == substring[i])

{

kmp:

i++;

k++;

next[i] = k;

if (k > max_k)

{

max_k = k;

}

}

else

{

k = next[k];

}

}

#ifdef __DEBUG__XU

for(i = 0; i < strlen(substring) + 1; i++)

{

printf("next[%d] = %d ", i, next[i]);

}

printf("/n");

getchar();

#endif

return max_k;

}