You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.

98 lines
2.1 KiB

package main
3 years ago
import (
"fmt"
"sort"
)
/***
295. 数据流的中位数
中位数是有序列表中间的数如果列表长度是偶数中位数则是中间两个数的平均值
例如
[2,3,4] 的中位数是 3
[2,3] 的中位数是 (2 + 3) / 2 = 2.5
设计一个支持以下两种操作的数据结构
void addNum(int num) - 从数据流中添加一个整数到数据结构中
double findMedian() - 返回目前所有元素的中位数
示例
addNum(1)
addNum(2)
findMedian() -> 1.5
addNum(3)
findMedian() -> 2
进阶:
如果数据流中所有整数都在 0 100 范围内你将如何优化你的算法
如果数据流中 99% 的整数都在 0 100 范围内你将如何优化你的算法
3 years ago
*/
func main() {
3 years ago
finder := Constructor()
finder.AddNum(1)
finder.AddNum(2)
fmt.Println(finder.FindMedian())
finder.AddNum(3)
fmt.Println(finder.FindMedian())
}
type MedianFinder struct {
Nums []int
}
/** initialize your data structure here. */
func Constructor() MedianFinder {
3 years ago
return MedianFinder{[]int{}}
}
3 years ago
func (this *MedianFinder) AddNum(num int) {
index := BinaryQuery(this.Nums, num)
if index == -1 {
var i []int
i = append(i, num)
this.Nums = append(i, this.Nums...)
} else {
a := append(this.Nums[:index], num)
this.Nums = append(a, this.Nums[index:]...)
}
}
func (this *MedianFinder) FindMedian() float64 {
3 years ago
i := len(this.Nums)
ii := i / 2
if i%2 == 0 {
return float64(this.Nums[ii])
}
return float64(this.Nums[ii]+this.Nums[ii-1]) / 2
}
/**
* Your MedianFinder object will be instantiated and called as such:
* obj := Constructor();
* obj.AddNum(num);
* param_2 := obj.FindMedian();
3 years ago
*/
// BinaryQuery 二分查找的实现,如果查找成功返回索引;否则返回-1
func BinaryQuery(list []int, target int) int {
// 定义并初始化low和high,声明mid
low, high := 0, len(list)-1
// 前提必须进行排序
sort.Ints(list)
for low <= high {
mid := (low + high) / 2
if list[mid] == target {
return mid
} else if list[mid] > target {
high = mid - 1
} else {
low = mid + 1
}
}
return -1
}