84 lines
2.5 KiB
C
84 lines
2.5 KiB
C
#include <stdlib.h>
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#include <stdio.h>
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#include <stdbool.h>
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#include <string.h>
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#define ENALBE_LOG 1
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#if ENALBE_LOG == 1
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#define DEBUG_LOG(...) printf(__VA_ARGS__)
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#else
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#define DEBUG_LOG(...)
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#endif
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char* longestPalindrome(char * input_str) {
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const size_t len = strlen(input_str) + 1; // Include null termination
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size_t start = 0;
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size_t end = 0;
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size_t c_start = 0;
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size_t c_end = 0;
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while (start < len) {
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bool is_palindrome = false;
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end = start;
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DEBUG_LOG("start: %lu\n", start);
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for (size_t i = start; i < len; ++i) {
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const size_t dist = end - start + 1;
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is_palindrome = false;
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DEBUG_LOG(" dist: %lu:\n", dist);
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for (size_t j = 0; j < dist; ++j) {
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const size_t start_it = start + j;
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const size_t end_it = end - j;
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DEBUG_LOG(" [%lu]%c = [%lu]%c: %s\n",start_it, input_str[start_it], end_it, input_str[end_it], input_str[start_it] == input_str[end_it] ? "true" : "false");
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if (input_str[start_it] == input_str[end_it]) {
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is_palindrome = true;
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} else {
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is_palindrome = false;
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}
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}
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if (is_palindrome) break;
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++end;
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}
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DEBUG_LOG("extracted: ");
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for (size_t i = 0; i < end - start + 1; ++i) {
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DEBUG_LOG("%c", input_str[start + i]);
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}
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DEBUG_LOG("\n");
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DEBUG_LOG("[%lu] -> [%lu], c: [%lu] -> [%lu]\n", start, end, c_start, c_end);
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DEBUG_LOG("\n");
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if (is_palindrome && end - start > c_end - c_start) {
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c_start = start;
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c_end = end;
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DEBUG_LOG("candidate: %lu -> %lu\n", c_start, c_end);
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}
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++start;
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}
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DEBUG_LOG("wow\n");
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DEBUG_LOG("[%lu] -> [%lu]: size %lu\n", c_start, c_end, c_end - c_start + 1);
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char* str = (char*)malloc((c_end - c_start + 2) * sizeof(char));
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memcpy(str, input_str + start, (c_end - c_start + 1) * sizeof(char));
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str[c_end - c_start + 1] = '\0';
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return str;
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}
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void print_hex(const char* str) {
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const size_t size = strlen(str) + 1; // Size of string with null termination
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for (size_t i = 0; i < size; ++i) {
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printf("0x%02x", str[i]);
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if (i < size - 1) printf(" ");
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else printf("\n");
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}
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}
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int main() {
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const char* input = "cbbd";
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printf("input: %s\n", input);
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char* str = longestPalindrome(input);
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printf("%s\n", str);
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free(str);
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return 0;
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}
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