From a11d45d64e23dbb32600b8176f372630d6bce940 Mon Sep 17 00:00:00 2001
From: mnerv <me@mononerv.dev>
Date: Fri, 6 Oct 2023 09:54:24 +0200
Subject: [PATCH] Half done 5. leetcode

---
 leetcode/longestpalindromicsubstr.c | 85 +++++++++++++++++++++++++++++
 1 file changed, 85 insertions(+)
 create mode 100644 leetcode/longestpalindromicsubstr.c

diff --git a/leetcode/longestpalindromicsubstr.c b/leetcode/longestpalindromicsubstr.c
new file mode 100644
index 0000000..b69c764
--- /dev/null
+++ b/leetcode/longestpalindromicsubstr.c
@@ -0,0 +1,85 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <stdbool.h>
+#include <string.h>
+
+#define ENALBE_LOG 1
+
+#if ENALBE_LOG == 1
+#define DEBUG_LOG(...) printf(__VA_ARGS__)
+#else
+#define DEBUG_LOG(...)
+#endif
+
+char* longestPalindrome(char * input_str) {
+    const size_t len  = strlen(input_str) + 1;     // Include null termination
+    size_t start = 0;
+    size_t end   = 0;
+
+    size_t c_start = 0;
+    size_t c_end   = 0;
+    bool is_first = true;
+
+    while (start < len) {
+        bool is_palindrome = false;
+        end = start;
+        DEBUG_LOG("start: %llu\n", start);
+        for (size_t i = start; i < len; ++i) {
+            const size_t dist = end - start + 1;
+            is_palindrome = false;
+            DEBUG_LOG("    dist: %llu:\n", dist);
+            for (size_t j = 0; j < dist; ++j) {
+                const size_t start_it = start + j;
+                const size_t end_it   = end - j;
+                DEBUG_LOG("        [%llu]%c = [%llu]%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");
+                if (input_str[start_it] == input_str[end_it]) {
+                    is_palindrome = true;
+                } else {
+                    is_palindrome = false;
+                }
+            }
+            if (is_palindrome && end - start > c_end - c_start) break;
+            ++end;
+        }
+        DEBUG_LOG("extracted: ");
+        for (size_t i = 0; i < end - start + 1; ++i) {
+            DEBUG_LOG("%c", input_str[start + i]);
+        }
+        DEBUG_LOG("\n");
+        DEBUG_LOG("[%llu] -> [%llu], c: [%llu] -> [%llu]\n", start, end, c_start, c_end);
+        DEBUG_LOG("\n");
+        if (is_palindrome && (end - start > c_end - c_start || is_first)) {
+            is_first = false;
+            c_start = start;
+            c_end   = end;
+            DEBUG_LOG("candidate: %llu -> %llu\n", c_start, c_end);
+        }
+        ++start;
+    }
+
+    DEBUG_LOG("wow\n");
+    DEBUG_LOG("[%llu] -> [%llu]: size %llu\n", c_start, c_end, c_end - c_start + 1);
+    char* str = (char*)malloc((c_end - c_start + 2) * sizeof(char));
+    memcpy(str, input_str + start, (c_end - c_start + 1) * sizeof(char));
+    str[c_end - c_start + 1] = '\0';
+    return str;
+}
+
+void print_hex(const char* str) {
+    const size_t size = strlen(str) + 1;  // Size of string with null termination
+    for (size_t i = 0; i < size; ++i) {
+        printf("0x%02x", str[i]);
+        if (i < size - 1) printf(" ");
+        else printf("\n");
+    }
+}
+
+int main() {
+    const char* input = "cbbd";
+    printf("input: %s\n", input);
+    char* str = longestPalindrome(input);
+    printf("%s\n", str);
+    free(str);
+    return 0;
+}
+