CF9C Hexadecimal's Numbers

    • 154通过
    • 434提交
  • 题目来源 CodeForces 9C
  • 评测方式 RemoteJudge
  • 标签 枚举,暴力 进制 递归 队列
  • 难度 普及-
  • 时空限制 1000ms / 64MB

题解

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    题意翻译

    输入n,输出1-n的自然数中各数位只包含0和1的数的个数。 Translated by @Lolierl

    题目描述

    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.

    输入输出格式

    输入格式:

    Input data contains the only number $ n $ ( $ 1<=n<=10^{9} $ ).

    输出格式:

    Output the only number — answer to the problem.

    输入输出样例

    输入样例#1: 复制
    10
    
    输出样例#1: 复制
    2

    说明

    For $ n $ = 10 the answer includes numbers 1 and 10.

    提示
    标程仅供做题后或实在无思路时参考。
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