가장 먼 노드

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
function solution(n, edge) {
  if (edge.length === 0) {
    return 1;
  }

  const arr = Array.from({length: n + 1}, () => []);

  edge.forEach(e => {
    arr[e[0]].push(e[1]);
    arr[e[1]].push(e[0]);
  });

  let input = [1];
  let visited = new Set();
  
  const getDepth = input => {
    let set = new Set();
    input.forEach(num => {
      const vertexes = arr[num];
      vertexes.forEach(v => {
        if (!visited.has(v)) {
          set.add(v);
        }
      })
    });
    
    return Array.from(set);
  }
  
  let lastInput = null;
  do {
    visited = new Set([...visited, ...input]);
    lastInput = input;
    input = getDepth(input);
  } while(input.length);

  return lastInput.length;
}