One beautiful July morning a terrible thing happened in Mainframe: a mean virus Megabyte somehow got access to the memory of his not less mean sister Hexadecimal. He loaded there a huge amount of n different natural numbers from 1 to n to obtain total control over her energy.
But his plan failed. The reason for this was very simple: Hexadecimal didn't perceive any information, apart from numbers written in binary format. This means that if a number in a decimal representation contained characters apart from 0 and 1, it was not stored in the memory. Now Megabyte wants to know, how many numbers were loaded successfully.
Input
Input data contains the only number n (1 ≤ n ≤ 109).
Output
Output the only number — answer to the problem.
Example
Input
10
Output
2
Note
For n = 10 the answer includes numbers 1 and 10.
给你一个数,求1到这个数中有多少个只有1,0组成的数
解题思路:可以深搜,也可以直接构造
1 #include<stdio.h> 2 3 long long sum, sum1; 4 5 void dfs(long long a) { 6 if(sum<a) 7 return ; 8 sum1++; 9 dfs(a*10); 10 dfs(a*10+1); 11 } 12 13 int main() { 14 while(scanf("%lld", &sum)!=EOF) { 15 sum1 = 0; 16 17 dfs(1); 18 19 printf("%lld\n", sum1); 20 } 21 return 0; 22 }
【推荐】编程新体验,更懂你的AI,立即体验豆包MarsCode编程助手
【推荐】凌霞软件回馈社区,博客园 & 1Panel & Halo 联合会员上线
【推荐】抖音旗下AI助手豆包,你的智能百科全书,全免费不限次数
【推荐】轻量又高性能的 SSH 工具 IShell:AI 加持,快人一步
· Linux glibc自带哈希表的用例及性能测试
· 深入理解 Mybatis 分库分表执行原理
· 如何打造一个高并发系统?
· .NET Core GC压缩(compact_phase)底层原理浅谈
· 现代计算机视觉入门之:什么是图片特征编码
· 手把手教你在本地部署DeepSeek R1,搭建web-ui ,建议收藏!
· Spring AI + Ollama 实现 deepseek-r1 的API服务和调用
· 数据库服务器 SQL Server 版本升级公告
· 程序员常用高效实用工具推荐,办公效率提升利器!
· C#/.NET/.NET Core技术前沿周刊 | 第 23 期(2025年1.20-1.26)