Remove Max Number of Edges to Keep Graph Fully Traversable

export function maxNumEdgesToRemove(n: number, edges: number[][]): number {
  const alice = new UnionFind(n);
  const bob = new UnionFind(n);
 
  let answer = 0;
  for (const [type, u, v] of edges) {
    if (type !== 3) continue;
    if (!(alice.union(u - 1, v - 1) && bob.union(u - 1, v - 1))) {
      answer += 1;
    }
  }
 
  for (const [type, u, v] of edges) {
    if (type === 3) continue;
    if (type === 1 && !alice.union(u - 1, v - 1)) {
      answer += 1;
    } else if (type === 2 && !bob.union(u - 1, v - 1)) {
      answer += 1;
    }
  }
 
  return alice.isUnited && bob.isUnited ? answer : -1;
}
 
class UnionFind {
  private readonly parents: number[];
  groupCount: number;
 
  constructor(n: number) {
    this.parents = Array.from({ length: n }, (_, i) => i);
    this.groupCount = n;
  }
 
  find(x: number): number {
    if (x !== this.parents[x]) {
      this.parents[x] = this.find(this.parents[x]);
    }
    return this.parents[x];
  }
 
  union(x: number, y: number): boolean {
    const parentX = this.find(x);
    const parentY = this.find(y);
    if (parentX === parentY) {
      return false;
    }
    this.parents[parentX] = parentY;
    this.groupCount -= 1;
    return true;
  }
 
  get isUnited() {
    return this.groupCount === 1;
  }
}