code: func (sis *SortedIntSet) incr(num int) {
  	if sis.useTreeMap {
  		val, ok := sis.dict[num]
  		if !ok {
  			sis.dict[num] = 1
  		} else {
  			sis.dict[num] = 1 + val
  		}
  		return
  	}
  
  	for i, v := range sis.values {
  		if v == num {
  			sis.counts[i]++
  			return
  		} else if num < v {
  			// insert here
  			sis.values = append(sis.values[:i], append([]int{num}, sis.values[i:]...)...)
  			sis.counts = append(sis.counts[:i], append([]int{1}, sis.counts[i:]...)...)
  			return
  		}
  	}
  
  	// append
  	sis.values = append(sis.values, num)
  	sis.counts = append(sis.counts, 1)
  
  	if len(sis.values) == TREE_MAP_CUTOVER {
  		sis.useTreeMap = true
  		for i, v := range sis.values {
  			sis.dict[v] = sis.counts[i]
  		}
  	}
  }
docs: // Adds this state ot the set