private void search(String[] words, int i, PalTrieNode root, List <List <int> > res)
{
for (int j = 0; j < words[i].Length; j++)
{
if (root.index >= 0 && root.index != i && isPalindrome(words[i], j, words[i].Length - 1))
{
res.Add(Arrays.AsList(i, root.index));
}
root = root.next[words[i][j] - 'a'];
if (root == null)
{
return;
}
}
foreach (int j in root.list)
{
if (i == j)
{
continue;
}
res.Add(Arrays.AsList(i, j));
}
}
public List <List <int> > palindromePairs(String[] words)
{
List <List <int> > res = new List <List <int> >();
PalTrieNode root = new PalTrieNode();
for (int i = 0; i < words.Length; i++)
{
addWord(root, words[i], i);
}
for (int i = 0; i < words.Length; i++)
{
search(words, i, root, res);
}
return(res);
}
private void addWord(PalTrieNode root, String word, int index)
{
for (int i = word.Length - 1; i >= 0; i--)
{
int j = word[i] - 'a';
if (root.next[j] == null)
{
root.next[j] = new PalTrieNode();
}
if (isPalindrome(word, 0, i))
{
root.list.Add(index);
}
root = root.next[j];
}
root.list.Add(index);
root.index = index;
}