Create 0295-find-median-from-data-stream.go

Accepted submission: _https://leetcode.com/submissions/detail/870802584/_

go/0295-find-median-from-data-stream.go

@@ -0,0 +1,50 @@
+type IntHeap []int
+func (h IntHeap) Len() int           { return len(h) }
+func (h IntHeap) Less(i, j int) bool { return h[i] < h[j] }
+func (h IntHeap) Swap(i, j int)      { h[i], h[j] = h[j], h[i] }
+func (h *IntHeap) Push(x interface{}) {*h = append(*h, x.(int))}
+func (h *IntHeap) Pop() interface{} {
+	old := *h
+	n := len(old)
+	x := old[n-1]
+	*h = old[0 : n-1]
+	return x
+}
+
+type MedianFinder struct {
+    small IntHeap
+    large IntHeap
+}
+
+
+func Constructor() MedianFinder {
+    return MedianFinder{small: IntHeap{}, large: IntHeap{}}
+}
+
+
+func (this *MedianFinder) AddNum(num int)  {
+    if len(this.large) > 0 && num > this.large[0] {
+        heap.Push(&this.large, num)
+    } else {
+        heap.Push(&this.small, -1 * num)
+    }
+
+    if len(this.small) > len(this.large) + 1 {
+        val := -1 * heap.Pop(&this.small).(int)
+        heap.Push(&this.large, val)
+    }
+    if len(this.large) > len(this.small) + 1 {
+        val := heap.Pop(&this.large).(int)
+        heap.Push(&this.small, -1 * val)
+    }
+}
+
+
+func (this *MedianFinder) FindMedian() float64 {
+    if len(this.small) > len(this.large) {
+        return float64(-1 * this.small[0])
+    } else if len(this.large) > len(this.small) {
+        return float64(this.large[0])
+    }
+    return float64(-1 * this.small[0] + this.large[0]) / 2
+}