public string AlienOrder(string[] words)
{
int len = 0;
for (int i = 0; i < words.Length; i++)
{
len = Math.Max(len, words[i].Length);
}
var g = new Graph();
for (int i = 0; i < words.Length; i++)
{
for (int l = 0; l < words[i].Length; l++)
{
g.AddNode(words[i][l]);
}
}
var skip = new bool[words.Length];
for (int l = 0; l < len; l++)
{
for (int i = 0; i < words.Length - 1; i++)
{
if (skip[i + 1])
{
continue;
}
if (l >= words[i].Length)
{
continue;
}
if (words[i][l] == words[i + 1][l])
{
continue;
}
try
{
g.InsertEdgeOrdered(words[i][l], words[i + 1][l]);
}
catch
{
return(string.Empty);
}
skip[i + 1] = true;
}
}
return(TopologicalSorter.SortToString(g));
}
