yelp OA

Yelp can recommend businesses based on a distance you’re willing to travel.

Given a distance input and a connected acyclic graph of businesses with edges as distances, return the list of names of businesses within the distance input.


  • starting business: a Business object to start from
  • distance: int


  • list of str: A list of Business names that are within the given distance of the starting Business

Distance is inclusive, meaning if a business is 5 away, then a distance input of 5 means that business IS reachable.

The return value should NOT have the name of the starting business. Therefore, if no businesses are within the given distance, return an empty list.

The return value is NOT required to be sorted.


Consider the following graph with distances where business A is the starting business.

         /  \
      2 /    \ 4
       /      \
      B        C
        \ 5

findReachableBusinesses(A, 1); // should return an empty list
findReachableBusinesses(A, 2); // should return ["B"]
findReachableBusinesses(A, 3); // should also return ["B"]
findReachableBusinesses(A, 4); // should return ["B", "C"]
findReachableBusinesses(A, 7); // should return ["B", "C", "D"]

 * Business class that consists of a business name and a hashmap of nearby businesses.
class Business {
     * The name of the business.
    String name;

     * A Map of nearbyBusinesses where the key is the nearby Business object
     * and the value is distance from the current Business to the nearby Business.
    Map<Business, Integer> nearbyBusinesses;

    public Business(String name) { = name;
        this.nearbyBusinesses = new HashMap<>();

    public String getName() {

    public Map<Business, Integer> getNearbyBusinesses() {
        return this.nearbyBusinesses;

class Solution {
	public static List<String> findReachableBusinesses(Business startingBusiness, int distance) {
		// todo


昨天晚上做的yelp OA,运气比较好抽的是最简单的Open_Hour_Ratio, input是time interval 代表一个人的休息时间 和 list of time intervals 代表一个餐厅开门时间的interval, output 休息时间且餐厅开门 占 总休息时间的ratio。 分 四种情况讨论就行了,也没有什么刁钻的corner case。

刚完成的OA, 就是那到经典得Active Business,15分钟做完,终于让我碰到一次原题了,真是爽快哈哈