当前位置:网站首页>(LeetCode)两数之和
(LeetCode)两数之和
2022-07-06 15:58:00 【[email protected]】
给定一个整数数组 nums 和一个整数目标值 target,请你在该数组中找出 和为目标值 target 的那 两个 整数,并返回它们的数组下标。
你可以假设每种输入只会对应一个答案。但是,数组中同一个元素在答案里不能重复出现。
你可以按任意顺序返回答案。
示例 1:
输入:nums = [2,7,11,15], target = 9
输出:[0,1]
解释:因为 nums[0] + nums[1] == 9 ,返回 [0, 1] 。
示例 2:
输入:nums = [3,2,4], target = 6
输出:[1,2]
示例 3:
输入:nums = [3,3], target = 6
输出:[0,1]
提示:
2 <= nums.length <= 104
-109 <= nums[i] <= 109
-109 <= target <= 109
只会存在一个有效答案
进阶:你可以想出一个时间复杂度小于 O(n2) 的算法吗?
Code:
class Solution
{
public:
// 输入:整数数组+整数目标值
// 输出:组成目标整数的两个数组元素的下标(任意顺序)
vector<int> twoSum(vector<int> &nums,int target)
{
// unordered_map基于哈希表实现,查找的时间复杂度较低O(1)
unordered_map<int,int> m;
// map基于红黑树实现,查找的时间复杂度O(n)
for(int i=0;i<nums.size();i++)
{
// 遍历,如果能组成目标整数,则输出下标
if(m.count(target-nums[i]))
{
return {m[target-nums[i]],i};
}
// 将前面查找过的数据存入unordered_map,以便与后面未查找过的数据匹配
m[nums[i]]=i;
}
// 未找到则返回空
return {};
}
};
来源:力扣(LeetCode)
链接:https://leetcode.cn/problems/two-sum
Reference:
C++ map和unordered_map的区别和联系以及map的使用_m0_67401660的博客-CSDN博客_unordered_map和map的区别
C++ unordered_map_永远爱好技术的王师傅的博客-CSDN博客_c++ unordered_map
版权声明
本文为[[email protected]]所创,转载请带上原文链接,感谢
https://blog.csdn.net/qq_40728667/article/details/125586619
边栏推荐
- Realize colorful lines and shape your heart
- Flutter life cycle
- Without CD, I'll teach you a trick to restore the factory settings of win10 system
- 传统企业要为 Web3 和去中心化做的 11 个准备
- B站大佬用我的世界搞出卷積神經網絡,LeCun轉發!爆肝6個月,播放破百萬
- COSCon'22 社区召集令来啦!Open the World,邀请所有社区一起拥抱开源,打开新世界~
- Efficient ETL Testing
- 基础图表解读“东方甄选”爆火出圈数据
- Experiment 4: installing packages from Gui
- MySQL connected vscode successfully, but this error is reported
猜你喜欢
PDF批量拆分、合并、书签提取、书签写入小工具
【通信】两层无线 Femtocell 网络上行链路中的最优功率分配附matlab代码
What can be done for traffic safety?
Résumé des connaissances de gradle
氢创未来 产业加速 | 2022氢能专精特新创业大赛报名通道开启!
B 站弹幕 protobuf 协议还原分析
Coscon'22 community convening order is coming! Open the world, invite all communities to embrace open source and open a new world~
Modules that can be used by both the electron main process and the rendering process
电脑重装系统u盘文件被隐藏要怎么找出来
None of the strongest kings in the monitoring industry!
随机推荐
资产安全问题或制约加密行业发展 风控+合规成为平台破局关键
Docker starts MySQL and -emysql_ ROOT_ Password = my secret PW problem solving
Isomorphism + cross end, knowing applet +kbone+finclip is enough!
Without CD, I'll teach you a trick to restore the factory settings of win10 system
The method of reinstalling win10 system is as simple as that
Computer reinstallation system teaching, one click fool operation, 80% of people have learned
A novice asks a question. I am now deployed on a single machine. I submitted an SQL job and it runs normally. If I restart the service job, it will disappear and I will have to
The programmer said, "I'm 36 years old, and I don't want to be rolled, let alone cut."
Stop saying that microservices can solve all problems
Restoration analysis of protobuf protocol of bullet screen in station B
Dockermysql modifies the root account password and grants permissions
flinksql select id ,count(*) from a group by id .
基于PaddlePaddle平台(EasyDL)设计的人脸识别课堂考勤系统
What should I do if the USB flash disk data is formatted and how can I recover the formatted USB flash disk data?
为了交通安全,可以做些什么?
吴恩达2022机器学习课程评测来了!
MySQL connected vscode successfully, but this error is reported
The important data in the computer was accidentally deleted by mistake, which can be quickly retrieved by this method
JS addition, deletion, modification and query of JSON array
Daily question brushing record (XV)