private void search(PalindromePairsTrie root, String[] words, int i, IList <IList <int> > result)
{
int len = words[i].Length;
for (int j = 0; j < len && root != null; j++)
{
if (root.pos >= 0 && i != root.pos && IsPalindrome(words[i], j, len - 1))
{
result.Add(new List <int> ()
{
i, root.pos
});
}
char ch = words[i][j];
root = root.nodes[ch - 'a'];
}
if (root != null && root.palins.Count > 0)
{
foreach (var j in root.palins)
{
if (j != i)
{
result.Add(new List <int> ()
{
i, j
});
}
}
}
}
public IList <IList <int> > PalindromePairs_b(string[] words)
{
IList <IList <int> > result = new List <IList <int> > ();
PalindromePairsTrie trie = new PalindromePairsTrie();
for (int i = 0; i < words.Length; i++)
{
add(trie, words[i], i);
}
for (int i = 0; i < words.Length; i++)
{
search(trie, words, i, result);
}
return(result);
}
private void add(PalindromePairsTrie root, String word, int pos)
{
for (int i = word.Length - 1; i >= 0; i--)
{
char ch = word[i];
if (IsPalindrome(word, 0, i))
{
root.palins.Add(pos);
}
if (root.nodes[ch - 'a'] == null)
{
root.nodes[ch - 'a'] = new PalindromePairsTrie();
}
root = root.nodes[ch - 'a'];
}
root.pos = pos;
root.palins.Add(pos);
}
