python_java_go_c++_295. 数据流的中位数
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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 到 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 到 100 范围内,你将如何优化你的算法?
1、python:
import heapq import json class MedianFinder: def __init__(self): self.queMin = list() self.queMax = list() def addNum(self, num: int) -> None: queMin_ = self.queMin queMax_ = self.queMax if not queMin_ or num <= -queMin_[0]: heapq.heappush(queMin_, -num) if len(queMax_) + 1 < len(queMin_): heapq.heappush(queMax_, -heapq.heappop(queMin_)) else: heapq.heappush(queMax_, num) if len(queMax_) > len(queMin_): heapq.heappush(queMin_, -heapq.heappop(queMax_)) def findMedian(self) -> float: queMin_ = self.queMin queMax_ = self.queMax if len(queMin_) > len(queMax_): return -queMin_[0] return (-queMin_[0] + queMax_[0]) / 2 if __name__ == '__main__': command = json.loads(input().strip()) num_pool = json.loads(input().strip()) finder = MedianFinder() for i, m in enumerate(command): if m == "MedianFinder": pass elif m == "addNum": finder.addNum(num_pool[i][0]) elif m == "findMedian": print(finder.findMedian())View Code
2、java:
疑问:java有像python range()那样限制吗?有像python的enumerate()方法吗?
import com.alibaba.fastjson.JSON; import java.nio.charset.StandardCharsets; import java.util.PriorityQueue; import java.util.Scanner; class MedianFinder { PriorityQueue<Integer> queMin; PriorityQueue<Integer> queMax; public MedianFinder() { queMin = new PriorityQueue<Integer>((a, b) -> (b - a)); queMax = new PriorityQueue<Integer>((a, b) -> (a - b)); } public void addNum(int num) { if (queMin.isEmpty() || num <= queMin.peek()) { queMin.offer(num); if (queMax.size() + 1 < queMin.size()) { queMax.offer(queMin.poll()); } } else { queMax.offer(num); if (queMax.size() > queMin.size()) { queMin.offer(queMax.poll()); } } } public double findMedian() { if (queMin.size() > queMax.size()) { return queMin.peek(); } return (queMin.peek() + queMax.peek()) / 2.0; } } class Main { public static void main(String[] args) { Scanner cin = new Scanner(System.in, StandardCharsets.UTF_8.name()); String[] command = JSON.parseObject(cin.nextLine(), String[].class); int[][] numPool = JSON.parseObject(cin.nextLine(), int[][].class); MedianFinder finder = new MedianFinder(); for (int i=0; i < command.length; i++) { if (command[i].equals("MedianFinder")) { // System.out.println(); } else if (command[i].equals("addNum")) { finder.addNum(numPool[i][0]); } else if (command[i].equals("findMedian")) { System.out.println(finder.findMedian()); } } } }View Code
3、go:
package main import ( "container/heap" "encoding/json" "fmt" "sort" ) type MedianFinder struct { queMin, queMax hp } func Constructor() MedianFinder { return MedianFinder{} } func (mf *MedianFinder) AddNum(num int) { minQ, maxQ := &mf.queMin, &mf.queMax if minQ.Len() == 0 || num <= -minQ.IntSlice[0] { heap.Push(minQ, -num) if maxQ.Len()+1 < minQ.Len() { heap.Push(maxQ, -heap.Pop(minQ).(int)) } } else { heap.Push(maxQ, num) if maxQ.Len() > minQ.Len() { heap.Push(minQ, -heap.Pop(maxQ).(int)) } } } func (mf *MedianFinder) FindMedian() float64 { minQ, maxQ := mf.queMin, mf.queMax if minQ.Len() > maxQ.Len() { return float64(-minQ.IntSlice[0]) } return float64(maxQ.IntSlice[0]-minQ.IntSlice[0]) / 2 } type hp struct{ sort.IntSlice } func (h *hp) Push(v interface{}) { h.IntSlice = append(h.IntSlice, v.(int)) } func (h *hp) Pop() interface{} { a := h.IntSlice; v := a[len(a)-1]; h.IntSlice = a[:len(a)-1]; return v } func main() { var commandInput string var numInput string if _, err := fmt.Scanf("%s\n%s", &commandInput, &numInput); err != nil { println("err:", err) return } command := make([]string, 0) if commandJsonErr := json.Unmarshal([]byte(commandInput), &command); commandJsonErr != nil { println(commandJsonErr) return } num := make([][]int, 0) if numJsonErr := json.Unmarshal([]byte(numInput),&num); numJsonErr != nil { println(numJsonErr) return } finder := Constructor() for i := 0; i < len(command); i++ { if command[i] == "MedianFinder" { //println() } else if command[i] == "addNum" { finder.AddNum(num[i][0]) } else if command[i] == "findMedian" { println(int32(finder.FindMedian())) } } }View Code
4、C++:
#include <vector> #include <queue> #include <iostream> #include ".\lib\json-3.9.1\single_include\nlohmann\json.hpp" using json = nlohmann::json; using namespace std; class MedianFinder { public: priority_queue<int, vector<int>, less<int>> queMin; priority_queue<int, vector<int>, greater<int>> queMax; MedianFinder() {} void addNum(int num) { if (queMin.empty() || num <= queMin.top()) { queMin.push(num); if (queMax.size() + 1 < queMin.size()) { queMax.push(queMin.top()); queMin.pop(); } } else { queMax.push(num); if (queMax.size() > queMin.size()) { queMin.push(queMax.top()); queMax.pop(); } } } double findMedian() { if (queMin.size() > queMax.size()) { return queMin.top(); } return (queMin.top() + queMax.top()) / 2.0; } }; int main() { string commandInput; getline(cin, commandInput); string numInput; getline(cin, numInput); auto commandJson = json::parse(commandInput, nullptr, false); vector<string> command = commandJson; auto numJson = json::parse(numInput, nullptr, false); vector<vector<int>> num = numJson; auto finder = MedianFinder(); for (int i=0; i<command.size(); i++) { if (command[i] == "MedianFinder") { // } else if (command[i] == "addNum") { finder.addNum(num[i][0]); } else if (command[i] == "findMedian") { cout << finder.findMedian() << endl; } } }View Code
标签:java,python,c++,num,command,queMax,return,MedianFinder,queMin 来源: https://www.cnblogs.com/zhangwenzhi/p/15195769.html