Solution 5

Author: obzva

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

@@ -0,0 +1,67 @@
+/*
+풀이
+- 이진탐색을 이용합니다
+Big O
+- N: 현재 MedianFinder.nums의 크기
+- AddNum
+  - Time complexity: O(N)
+    - bisect -> O(logN)
+	- slices.Insert -> O(N)
+  - Space complexity: O(1)
+- FindMedian
+  - Time complexity: O(1)
+  - Space complexity: O(1)
+*/
+
+import "slices"
+
+type MedianFinder struct {
+	nums []int
+}
+
+func Constructor() MedianFinder {
+	mf := MedianFinder{}
+	mf.nums = make([]int, 0)
+	return mf
+}
+
+func (this *MedianFinder) AddNum(num int) {
+	n := len(this.nums)
+	if n == 0 {
+		this.nums = append(this.nums, num)
+	} else {
+		idx := bisectLeft(this.nums, num)
+		this.nums = slices.Insert(this.nums, idx, num)
+	}
+}
+
+func (this *MedianFinder) FindMedian() float64 {
+	n := len(this.nums)
+	if n%2 == 0 {
+		return (float64(this.nums[n/2-1]) + float64(this.nums[n/2])) / 2
+	} else {
+		return float64(this.nums[n/2])
+	}
+}
+
+// ----- Helper -----
+func bisectLeft(arr []int, x int) int {
+	lo := 0
+	hi := len(arr)
+	for lo < hi {
+		mid := lo + (hi-lo)/2
+		if arr[mid] < x {
+			lo = mid + 1
+		} else {
+			hi = mid
+		}
+	}
+	return lo
+}
+
+/**
+ * Your MedianFinder object will be instantiated and called as such:
+ * obj := Constructor();
+ * obj.AddNum(num);
+ * param_2 := obj.FindMedian();
+ */