Updated algorithm to handle even numbered palindromes

Was only working with odds, since they have one letter at their center.
This change allows for a palindrome to have two letters at its center
(even numbered).

1 files changed, 25 insertions, 3 deletions

diff --git a/src/main.c b/src/main.c
index 20811a7..fcf8c1e 100644
--- a/src/main.c
+++ b/src/main.c
@@ -43,14 +43,36 @@ void find_largest_palindromes(char* data) {
   // 0 1 2 3 4 5 6
   // r a c e c a r
 
+  // 0 1 2 3 4 5
+  // a b c c b a
+
   while(data[cursor] != '\0') {
+    // Need to align with the center
+    // Advance end one to see if this is an even numbered palindrome
+    if(data[end + 1] != '\0') {
+      ++end;
+    }
+    // If it's not an even numbered, let's see if it's odd numbered
+    if(start > 0 && data[start] != data[end]) {
+      --start;
+    }
+    // Looks like it's not either, reset and continue
+    if(data[start] != data[end]) {
+      ++cursor;
+      start = cursor;
+      end = cursor;
+      continue;
+    }
+
+    // It seems we have found a palindrome, let's see how big...
     while(data[start] == data[end]) {
-      if(start > 0) {
-        --start;
-      }
       if(data[end + 1] != '\0') {
         ++end;
       }
+      if(start > 0) {
+        --start;
+      }
+
     }
     if(end - start - 1 > largest) {
       largest = end - start - 1;