123 lines
No EOL
3.1 KiB
JavaScript
123 lines
No EOL
3.1 KiB
JavaScript
class WAVLTree extends AVLTree {
|
|
isCorrectNode(node, recursive) {
|
|
if (!node) {
|
|
return true;
|
|
}
|
|
|
|
nodeDifferences(node).forEach(childRank => {
|
|
if ([1, 2].findIndex(childRank) == -1) {
|
|
return false;
|
|
}
|
|
});
|
|
|
|
if (node.type() == LEAF) {
|
|
return node.rank == 0;
|
|
}
|
|
|
|
return !(recursive ?? true) || (this.isCorrectNode(node.left) && this.isCorrectNode(node.right));
|
|
}
|
|
|
|
fixDelete(x, y, z, reversed, rotateLeft, rotateRight) {
|
|
let newRoot = x;
|
|
let [v, w] = [y.left, y.right];
|
|
|
|
if (reversed) {
|
|
[v, w] = [w, v];
|
|
}
|
|
|
|
let wDiff = nodeDifference(w, y);
|
|
|
|
if (wDiff == 1 && y.parent) {
|
|
newRoot = rotateLeft(y.parent);
|
|
|
|
y.promote();
|
|
z.demote();
|
|
|
|
if (z.type() == LEAF) {
|
|
z.demote();
|
|
}
|
|
} else if (wDiff == 2 && v && v.parent) {
|
|
rotateRight(v.parent);
|
|
newRoot = rotateLeft(v.parent);
|
|
|
|
v.promote().promote();
|
|
y.demote();
|
|
z.demote().demote();
|
|
}
|
|
|
|
return newRoot;
|
|
}
|
|
|
|
bottomUpDelete(x, parent) {
|
|
let xDiff = nodeDifference(x, parent);
|
|
if (xDiff != 3 || !parent) {
|
|
return;
|
|
}
|
|
|
|
let y = (parent.left === x) ? parent.right : parent.left;
|
|
let yDiff = nodeDifference(y, parent);
|
|
|
|
while (parent && xDiff == 3 && y && (yDiff == 2 || nodeDifferences(y).equals([2, 2]))) {
|
|
parent.demote();
|
|
if (yDiff != 2) {
|
|
y.demote();
|
|
}
|
|
|
|
x = parent;
|
|
parent = x.parent;
|
|
if (!parent) {
|
|
return;
|
|
}
|
|
|
|
let y = (parent.left === x) ? parent.right : parent.left;
|
|
|
|
xDiff = nodeDifference(x, parent);
|
|
yDiff = nodeDifference(y, parent);
|
|
}
|
|
|
|
if (!parent) {
|
|
return;
|
|
}
|
|
|
|
let rotatingAroundRoot = parent.parent == null;
|
|
let newRoot = parent;
|
|
|
|
let parentNodeDiffs = nodeDifferences(parent);
|
|
if (parentNodeDiffs.sort().equals([1, 3])) {
|
|
if (parent.left === x) {
|
|
newRoot = this.fixDelete(x, parent.right, parent, false, rotateLeft, rotateRight);
|
|
} else {
|
|
newRoot = this.fixDelete(x, parent.left, parent, true, rotateRight, rotateLeft);
|
|
}
|
|
}
|
|
|
|
if (rotatingAroundRoot) {
|
|
this.root = newRoot;
|
|
}
|
|
}
|
|
|
|
deleteFixup(y, parent) {
|
|
let z = (y) ? y : parent;
|
|
|
|
if (nodeDifferences(z).equals([2, 2])) {
|
|
z.demote();
|
|
}
|
|
|
|
if (!parent) {
|
|
return;
|
|
}
|
|
|
|
[parent.left, parent.right].forEach(y => {
|
|
if (nodeDifference(y, parent) == 3) {
|
|
this.bottomUpDelete(y, parent);
|
|
}
|
|
});
|
|
}
|
|
|
|
deleteRebalance(node, parent) {
|
|
while (node || parent) {
|
|
this.deleteFixup(node, parent);
|
|
[node, parent] = parent, (parent) ? parent.parent : null;
|
|
}
|
|
}
|
|
} |