LeetCode 702. Search in a Sorted Array of Unknown Size
原题链接在这里:https://leetcode.com/problems/search-in-a-sorted-array-of-unknown-size/
题目:
Given an integer array sorted in ascending order, write a function to search target
in nums
. If target
exists, then return its index, otherwise return -1
. However, the array size is unknown to you. You may only access the array using an ArrayReader
interface, where ArrayReader.get(k)
returns the element of the array at index k
(0-indexed).
You may assume all integers in the array are less than 10000
, and if you access the array out of bounds, ArrayReader.get
will return 2147483647
.
Example 1:
Input:array
= [-1,0,3,5,9,12],target
= 9
Output: 4
Explanation: 9 exists innums
and its index is 4
Example 2:
Input:array
= [-1,0,3,5,9,12],target
= 2
Output: -1
Explanation: 2 does not exist innums
so return -1
Note:
- You may assume that all elements in the array are unique.
- The value of each element in the array will be in the range
[-9999, 9999]
.
题解:
The range of index could not be over 20000. Because element raget is [-9999, 9999].
Guess the index using binary search, and call the reader.get() on the guess index.
If the return value cur > target, it could be either there is no such index, return is Integer.MAX_VALUE, or it exists, but value is larger. Either way, should continue guessing smaller index.
If cur < target, should continue guessing larger index.
If cur == target, return the guess index.
Time Complexity: O(logn). n = 20000.
Space:O(1).
AC Java:
class Solution {
public int search(ArrayReader reader, int target) {
int l = 0;
int r = 20000;
while(l <= r){
int mid = l + (r-l)/2;
int cur = reader.get(mid);
if(cur > target){
r = mid-1;
}else if(cur < target){
l = mid+1;
}else{
return mid;
}
} return -1;
}
}
Could use candidate call to get r. while (reader.get(r) < target). r *=2.
Then target index should be (r/2,r].
Time Complexity: O(logn).
Space: O(1).
AC Java:
class Solution {
public int search(ArrayReader reader, int target) {
int r = 1;
while(reader.get(r) < target){
r = r << 1;
} int l = r >> 1;
while(l <= r){
int mid = l + (r-l)/2;
int cur = reader.get(mid);
if(cur > target){
r = mid-1;
}else if(cur < target){
l = mid+1;
}else{
return mid;
}
} return -1;
}
}
LeetCode 702. Search in a Sorted Array of Unknown Size的更多相关文章
- 【LeetCode】702. Search in a Sorted Array of Unknown Size 解题报告 (C++)
作者: 负雪明烛 id: fuxuemingzhu 个人博客:http://fuxuemingzhu.cn/ 目录 题目描述 题目大意 解题方法 遍历 二分查找 日期 题目地址:https://lee ...
- [LeetCode] Search in a Sorted Array of Unknown Size 在未知大小的有序数组中搜索
Given an integer array sorted in ascending order, write a function to search target in nums. If tar ...
- [LeetCode] 033. Search in Rotated Sorted Array (Hard) (C++)
指数:[LeetCode] Leetcode 解决问题的指数 (C++/Java/Python/Sql) Github: https://github.com/illuz/leetcode 033. ...
- [array] leetcode - 33. Search in Rotated Sorted Array - Medium
leetcode - 33. Search in Rotated Sorted Array - Medium descrition Suppose an array sorted in ascendi ...
- LeetCode 81 Search in Rotated Sorted Array II [binary search] <c++>
LeetCode 81 Search in Rotated Sorted Array II [binary search] <c++> 给出排序好的一维有重复元素的数组,随机取一个位置断开 ...
- LeetCode 33 Search in Rotated Sorted Array [binary search] <c++>
LeetCode 33 Search in Rotated Sorted Array [binary search] <c++> 给出排序好的一维无重复元素的数组,随机取一个位置断开,把前 ...
- [leetcode]81. Search in Rotated Sorted Array II旋转过有序数组里找目标值II(有重)
This is a follow up problem to Search in Rotated Sorted Array, where nums may contain duplicates. 思路 ...
- Java for LeetCode 081 Search in Rotated Sorted Array II
Follow up for "Search in Rotated Sorted Array": What if duplicates are allowed? Would this ...
- [LeetCode] 81. Search in Rotated Sorted Array II 在旋转有序数组中搜索 II
Follow up for "Search in Rotated Sorted Array":What if duplicates are allowed? Would this ...
随机推荐
- Java随堂笔记三
今天学习了Java运算符的最后一部分 public static void main(String[] args) { //算数运算符:+ - * / % ++ -- // ...
- 300iq Contest 1 简要题解
300iq Contest 1 简要题解 咕咕咕 codeforces A. Angle Beats description 有一张\(n\times m\)的方阵,每个位置上标有*,+,.中的一种. ...
- k8s的学习
20191123 开始重头再学一遍k8 一 K8S的组件介绍
- ML学习笔记之LATEX数学公式基本语法
作者:@houkai本文为作者原创,转载请注明出处:https://www.cnblogs.com/houkai/p/3399646.html 0x00 概述 TEX 是Donald E. Knuth ...
- C# 网络连接中异常断线的处理:ReceiveTimeout, SendTimeout 及 KeepAliveValues(设置心跳)
C# 网络连接中异常断线的处理:ReceiveTimeout, SendTimeout 及 KeepAliveValues(设置心跳) 在使用 TcpClient 网络连接中常常会发生客户端连接异常断 ...
- React 的setState 理解
我们都知道在React中,setState() 方法是用来改变组件状态的,在项目中也一直用,也没有出现什么问题(使用方法太简单了),但今天看了一篇文章,提到了setState 使用时的两个注意点,加深 ...
- Android源码分析(二)-----如何编译修改后的framework资源文件
一 : 编译framework资源文件 如果修改android framework资源文件,需要先编译资源文件,然后再编译framework才可以正常引用, 进入项目目录 cd work/source ...
- OCR3:tesseract script
通过命令:tesseract -h 可查看 OCR操作脚本参数: 其中参数说明: –-oem:指定使用的算法,0:代表老的算法:1:代表LSTM算法:2:代表两者的结合:3:代表系统自己选择. –-p ...
- git 自定义log
个人记录防止忘记 log别名: git config --global alias.lg=log --color --graph --pretty=format:'%Cred%h%Creset -%C ...
- Spring MVC 上传、下载、显示图片
目录 1. 准备工作 1.1 数据库表准备 1.2 实体类 User 和 Mapper(DAO) 1.3 pom.xml 依赖包 1.4 SSM 框架的整合配置 2. 控制器 UserControll ...