[알고리즘] 입력 string이 다른 입력 string의 rotation인지를 단 한번의 sub string method를 호출해서 찾기

#include <stdio.h>

#include <string.h>

#include <malloc.h>

//-------------------------------------------------------

// DEFINED MACRO

//-------------------------------------------------------

#define str_print(x, ...)  printf("[%04u]"x, __LINE__, ##__VA_ARGS__)

typedef unsigned int uint32;

char* append_str(char *str1, char *str2)

{

uint32 idx = 0, res_idx = 0;

uint32 len1 = strlen(str1);

uint32 len2 = strlen(str2);

char *result = (char *)malloc(len1 + len2);

if (NULL == result) {

str_print("malloc(for size %u) is failed!!", len1 + len2);

goto end;

}

for (idx = 0; idx < len1; idx++) {

result[res_idx++] = str1[idx];

}

result[res_idx] = 0;

str_print("result = %u, %s\r\n", res_idx, result);

for (idx = 0; idx < len2; idx++) {

result[res_idx++] = str2[idx];

}

result[res_idx] = 0;

str_print("result = %s\r\n", result);

end:

return result;

}

bool is_substr(char *str1, char *str2)

{

bool ret = false;

uint32 tot_len = strlen(str1);

uint32 len2 = strlen(str2);

uint32 idx = 0, equ_cnt = 0, idx_str2 = 0;

for (idx = 0; idx < tot_len; idx++) {

str_print("%c, %c, %u, %u, %u\r\n", str1[idx], str2[idx_str2], idx_str2, len2, equ_cnt);

if (idx_str2 < len2 && str1[idx] == str2[idx_str2]) {

equ_cnt++;

idx_str2++;

} else {

idx_str2 = 0;

equ_cnt = 0;

}

if (equ_cnt == len2) {

break;

}

}

if (equ_cnt == len2) {

ret = true;

}

return ret;

}

bool is_rotation(char str1[], char str2[])

{

return is_substr(append_str(str2, str2), str1);

}

int main(void)

{

char *tgt_str = "terwa";

char *src_str = "water";

bool ret = is_rotation(tgt_str, src_str);

printf("%s is a substring of %s ? %s", (char *)tgt_str, (char *)src_str, (true == ret ? "true":"false"));

return 0;

}