| 6dd74de | | | 1 | export interface TreeData { |
| 6dd74de | | | 2 | parentById: Record<string, string>; |
| 6dd74de | | | 3 | childrenById: Record<string, string[]>; |
| 6dd74de | | | 4 | } |
| 6dd74de | | | 5 | |
| 6dd74de | | | 6 | export const findCommonAncestor = (id1: string, id2: string, { parentById }: TreeData) => { |
| 6dd74de | | | 7 | const visited = new Set(); |
| 6dd74de | | | 8 | let currentId = id1; |
| 6dd74de | | | 9 | |
| 6dd74de | | | 10 | // Edge case with self edges |
| 6dd74de | | | 11 | if (id1 === id2) { |
| 6dd74de | | | 12 | return parentById[id1] || 'root'; |
| 6dd74de | | | 13 | } |
| 6dd74de | | | 14 | |
| 6dd74de | | | 15 | while (currentId) { |
| 6dd74de | | | 16 | visited.add(currentId); |
| 6dd74de | | | 17 | if (currentId === id2) { |
| 6dd74de | | | 18 | return currentId; |
| 6dd74de | | | 19 | } |
| 6dd74de | | | 20 | currentId = parentById[currentId]; |
| 6dd74de | | | 21 | } |
| 6dd74de | | | 22 | |
| 6dd74de | | | 23 | currentId = id2; |
| 6dd74de | | | 24 | while (currentId) { |
| 6dd74de | | | 25 | if (visited.has(currentId)) { |
| 6dd74de | | | 26 | return currentId; |
| 6dd74de | | | 27 | } |
| 6dd74de | | | 28 | currentId = parentById[currentId]; |
| 6dd74de | | | 29 | } |
| 6dd74de | | | 30 | |
| 6dd74de | | | 31 | return 'root'; |
| 6dd74de | | | 32 | }; |