题目：

题解：

type MedianFinder struct {     nums        *redblacktree.Tree     total       int     left, right iterator }  func Constructor() MedianFinder {     return MedianFinder{nums: redblacktree.NewWithIntComparator()} }  func (mf *MedianFinder) AddNum(num int) {     if count, has := mf.nums.Get(num); has {         mf.nums.Put(num, count.(int)+1)     } else {         mf.nums.Put(num, 1)     }     if mf.total == 0 {         it := mf.nums.Iterator()         it.Next()         mf.left = iterator{it, 1}         mf.right = mf.left     } else if mf.total%2 == 1 {         if num < mf.left.Key().(int) {             mf.left.prev()         } else {             mf.right.next()         }     } else {         if mf.left.Key().(int) < num && num < mf.right.Key().(int) {             mf.left.next()             mf.right.prev()         } else if num >= mf.right.Key().(int) {             mf.left.next()         } else {             mf.right.prev()             mf.left = mf.right         }     }     mf.total++ }  func (mf *MedianFinder) FindMedian() float64 {     return float64(mf.left.Key().(int)+mf.right.Key().(int)) / 2 }  type iterator struct {     redblacktree.Iterator     count int }  func (it *iterator) prev() {     if it.count > 1 {         it.count--     } else {         it.Prev()         it.count = it.Value().(int)     } }  func (it *iterator) next() {     if it.count < it.Value().(int) {         it.count++     } else {         it.Next()         it.count = 1     } }