37 lines
769 B
TypeScript
37 lines
769 B
TypeScript
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import { concat, sum } from './array';
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export type Tree<T> = {
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node: T,
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children: Forest<T>;
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};
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export type Forest<T> = Tree<T>[];
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export function createLeaf<T>(node: T): Tree<T> {
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return { node, children: [] };
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}
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export function createTree<T>(node: T, children: Forest<T>): Tree<T> {
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return { node, children };
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}
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export function hasChildren<T>(t: Tree<T>): boolean {
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return t.children.length !== 0;
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}
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export function preorder<T>(t: Tree<T>): T[] {
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return [t.node, ...preorderF(t.children)];
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}
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export function preorderF<T>(ts: Forest<T>): T[] {
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return concat(ts.map(preorder));
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}
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export function countNodes<T>(t: Tree<T>): number {
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return preorder(t).length;
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}
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export function countNodesF<T>(ts: Forest<T>): number {
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return sum(ts.map(countNodes));
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}
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