void rotateRight(P y) { // zig
BT tmp;
P x = tmp.root();
BT::assignFrom(x, -y);
int& bx = (*x).balance();
int& by = (*y).balance();
BT::assignFrom(-y, +x);
BT::assignFrom(+x, y);
BT::assignFrom(y, x);
if (bx >= 0)
by++;
else
by -= bx - 1;
if (by <= 0)
bx++;
else
bx += by + 1;
}
void rotateLeft(P x) { // zag
BT tmp;
P y = tmp.root();
BT::assignFrom(y, +x);
int& bx = (*x).balance();
int& by = (*y).balance();
BT::assignFrom(+x, -y);
BT::assignFrom(-y, x);
BT::assignFrom(x, y);
if (by <= 0)
bx--;
else
bx -= by + 1;
if (bx >= 0)
by--;
else
by += bx - 1;
}
