private int[] iterate()
{
if (p == null)
{
initializePermutation();
updatePermutation();
return(p);
}//There is no permutation yet
//Previous permutation exists
for (int i = indexArray.Length - 1; i > 0; i--)
{
if (inOrder(indexArray[i - 1], indexArray[i]))
{
int tearingNumberIndex = i - 1;
//Reorder the tail of permutation
int startingIndex = tearingNumberIndex + 1;
int sortingLength = indexArray.Length - tearingNumberIndex - 1;
Array.Sort(indexArray, startingIndex, sortingLength);
//Search for the number to swap with tearing number
for (int j = tearingNumberIndex; j < indexArray.Length; j++)
{
//The number should be greater than tearing
if (inOrder(indexArray[tearingNumberIndex], indexArray[j]))
{
swapValues(tearingNumberIndex, j, indexArray);
break;
}
}
updatePermutation();
return(p);
}
}
int inversionIndex = nextInversionIndex();
if (inversions == 2 << (permutationLength / 2 - 1))
{
return(null); //There is no suitable permutations left
}
pairs1.SwapValuesAtIndex(inversionIndex);
resetIndexArray();
updatePermutation();
return(p);
}
