［抄题］: Given an array of integers with possible duplicates, randomly output the index of a given target number. You can assume that the given target number must exist in the array. Note:The array size can be very large. Solution that uses too much ext…

Given an array of integers with possible duplicates, randomly output the index of a given target number. You can assume that the given target number must exist in the array. Note: The array size can be very large. Solution that uses too much extra sp…

Question 398. Random Pick Index Solution 思路:重点是如果数据中有多个数target相等,要从这些数中随机取一个,根据例题 假设输入是: int[] nums = new int[]{1, 2, 3, 3, 3}; int target = 3; 模拟: 1 != target pass 2 != target pass 3 == target pick的概率 nextInt(1)==0的概率 1,返回这个index的概念是1 - 1/3 -1/3 = 1…

Given a singly linked list, return a random node's value from the linked list. Each node must have the same probability of being chosen. Follow up: What if the linked list is extremely large and its length is unknown to you? Could you solve this effi…

Given a singly linked list, return a random node's value from the linked list. Each node must have the same probability of being chosen. Follow up: What if the linked list is extremely large and its length is unknown to you? Could you solve this effi…

random.range和len函数的使用 一.random函数 1.random.random()和random.Random(): import random num = random.random()#生成0~1的随机浮点数0.6161288183675745 num2 = random.Random()#生成random模块里得Random类的一个实例,所以返回值是一串地址符<random.Random object at 0x036CFE38> #random.random()相当于…

//20160518 Math类常用方法 练习 package MyPackage; public class MathDemo {//定义主类和main方法 public static void main(String[] args) { System.out.println(Math.sqrt(16));// Math类常用方法:求平方根 System.out.println(Math.pow(2, 3));// Math类常用方法:多少的多少次方 System.out.println(Ma…

随机排序函数dbms_random.value()用法:select * from tablename order by dbms_random.value() 行数字段rownum用法:select * from tablename where rownum<=10…

import random # print(random.random()) # 随机浮点数,默认取0-1,不能指定范围# print(random.randint(1, 20)) # 随机整数,顾头顾尾# print(random.choice('sdfsd233')) # 随机取一个元素# print(random.sample('hello234234史蒂夫34', 4))#从序列中随机取几个元素,返回是一个list # f =random.uniform(1, 9) # 随机取浮点数,可…

  简单举个例子: drop table if exists demo1 create table demo1 ( id int primary key auto_increment, name ) ) desc demo1 -- 随机字符串函数用于插入数据 drop function if exists rand_str; delimiter // create function rand_str(size int,type int) ) begin ) ; ) '; ) default 'q…