code: func haveOverlap(a1, a2 []string) bool {
  	if len(a1) > len(a2) {
  		a1, a2 = a2, a1
  	}
  	m := map[string]bool{}
  
  	for _, val := range a1 {
  		m[val] = true
  	}
  	for _, val := range a2 {
  		if _, ok := m[val]; ok {
  			return true
  		}
  	}
  
  	return false
  }
docs: // search two arrays and return true if they have at least one common element; return false otherwise