public void Reorder(int start, int end)
{
byte maxLevel = orderLevels[start];
byte minLevel = maxLevel;
byte onlyOddLevels = maxLevel;
byte onlyEvenLevels = maxLevel;
for (int k = start + 1; k <= end; ++k) {
byte b = orderLevels[k];
if (b > maxLevel)
maxLevel = b;
else if (b < minLevel)
minLevel = b;
onlyOddLevels &= b;
onlyEvenLevels |= b;
}
if ((onlyEvenLevels & 1) == 0) // nothing to do
return;
if ((onlyOddLevels & 1) == 1) { // single inversion
Flip(start, end + 1);
return;
}
minLevel |= 1;
for (; maxLevel >= minLevel; --maxLevel) {
int pstart = start;
for (;;) {
for (;pstart <= end; ++pstart) {
if (orderLevels[pstart] >= maxLevel)
break;
}
if (pstart > end)
break;
int pend = pstart + 1;
for (; pend <= end; ++pend) {
if (orderLevels[pend] < maxLevel)
break;
}
Flip(pstart, pend);
pstart = pend + 1;
}
}
}