ready4god2513 · August 29, 2015 14:06 · Sep 26, 2014 · Sep 26, 2014 · Sep 26, 2014
diff --git a/gistfile1.rb b/gistfile1.rb
@@ -18,7 +18,7 @@ def pals_in_str(s)
 
   letters.each_with_index do |char, index|
     if char == letters.at(index + 1)
-      pals << build_pal(letters, char.concat(letters.at(index + 1)), index, (index + 1))
+      pals << build_pal(letters, char.dup.concat(letters.at(index + 1)), index, (index + 1))
     elsif letters.at(index - 1) == letters.at(index + 1)
       pals << build_pal(letters, char.dup, index, index)
     end

diff --git a/gistfile1.rb b/gistfile1.rb
@@ -20,7 +20,7 @@ def pals_in_str(s)
     if char == letters.at(index + 1)
       pals << build_pal(letters, char.concat(letters.at(index + 1)), index, (index + 1))
     elsif letters.at(index - 1) == letters.at(index + 1)
-      pals << build_pal(letters, char, index, index)
+      pals << build_pal(letters, char.dup, index, index)
     end
   end
 

diff --git a/gistfile1.rb b/gistfile1.rb
@@ -0,0 +1,47 @@
+def longest_palind(s)
+    # First find all palindromes.  The way we can do
+    # this is to scan through the letters searching for
+    # the middle.  We can find the middle by detecting a letter
+    # that meets one of two criteria- has the same letter before and after it,
+    # or is the same letter.  Once we have found that it is a palindrome,
+    # continue to expand the search finding the length.  Once we have the length
+    # extract the string and append to the array.  Sort the array by the longest
+    # and shift.
+    all_pals = pals_in_str(s)
+    puts all_pals.sort_by(&:length).reverse.first
+end
+
+def pals_in_str(s)
+  pals = []
+  len = s.length
+  letters = s.scan(/./)
+
+  letters.each_with_index do |char, index|
+    if char == letters.at(index + 1)
+      pals << build_pal(letters, char.concat(letters.at(index + 1)), index, (index + 1))
+    elsif letters.at(index - 1) == letters.at(index + 1)
+      pals << build_pal(letters, char, index, index)
+    end
+  end
+
+  pals
+end
+
+def build_pal(letters, data, start, stop)
+  steps = 0
+  match = true
+  while match
+    steps += 1
+    prev = letters.at(start - steps)
+    nexxt = letters.at(stop + steps)
+    match = false
+
+    if prev == nexxt
+      data.insert(0, prev)
+      data.insert(-1, nexxt)
+      match = true
+    end
+  end
+
+  data
+end
No results found