DFS
const solution = (arr, rootNode) => {
const visited = new Array(arr.length).fill(false);
const result = [];
const dfs = (node) => {
if (visited[node]) {
return;
}
visited[node] = true;
result.push(node);
path[node].forEach((n) => {
if (!visited[n]) {
dfs(n);
}
});
};
dfs(rootNode);
return result;
};