QuestionGetAncestors

package main

import "fmt"

type Services interface {
    AddService(service int, dependency int)
    GetAncestors(service int, depth int)
}

type ServiceManager struct {
    servicemap map[int][]int
}

func (servicemanager *ServiceManager) AddService(service, dependency int) {
    servicemanager.servicemap[service] = append(servicemanager.servicemap[service], dependency)
}

func (serviceManager *ServiceManager) GetAncestors(service, depth int) []int { //added depth
    visited := make(map[int]bool) //to avoid dupicate results
    var res []int
    var dfs func(service, depth int)
    dfs = func(service, depth int) {
        if depth == 0 {
            return
        }
        for _, dep := range serviceManager.servicemap[service] {
            if !visited[dep] {
                visited[dep] = true
                res = append(res, dep)
                dfs(dep, depth-1)
            }
        }
    }

    dfs(service, depth)
    return res
}

func main() {
    serviceManager := &ServiceManager{
        servicemap: make(map[int][]int),
    }
    serviceManager.AddService(0, 1)
    serviceManager.AddService(1, 2)
    fmt.Println(serviceManager.GetAncestors(0, 1))
    serviceManager.AddService(0, 3)
    serviceManager.AddService(3, 4)
    fmt.Println(serviceManager.GetAncestors(0, 2))
}