OCC '19 S2 - Rimuru's Number Game - Olympiads Online Judge

OCC '19 S2 - Rimuru's Number Game

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Points: 5

Time limit: 1.0s

Memory limit: 64M

Author:

zxyl

Problem types

It's Pookmeister's birthday, and Rimuru wants to give him a gift. Knowing that he loves the numbers $2$ ~2~ and $3$ ~3~, Rimuru wants to know how many different numbers less than or equal to $N$ ~N~ that only consist of digits that are either $2$ ~2~ or $3$ ~3~.

Subtasks

(20 points) $N \le 10^5$ ~N \le 10^5~
(80 points) No additional constraints.

Input Specification

A single integer $N$ ~N~ $(3 \le N \le 10^{18})$ ~(3 \le N \le 10^{18})~.

Output Specification

The answer to the problem, on a single line.

Sample Input 1

Sample Output 1

Explanation for Sample 1

The only two numbers are $2$ ~2~ and $3$ ~3~.

Sample Input 2

Sample Output 2

Explanation for Sample 2

The only valid numbers are $2$ ~2~, $3$ ~3~, $22$ ~22~, $23$ ~23~, $32$ ~32~ and $33$ ~33~.

Comments

-7

jaydenchu2003 commented on Feb. 12, 2020, 3:04 a.m.

Anyone got a faster way for python?

This comment is hidden due to too much negative feedback. Show it anyway.

2

CubixularHelix commented on Sept. 27, 2020, 2:57 a.m.

You don't need to check every number. Consider the implications of the numbers only having the digits 2 and 3.