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Competition Arena > TheAlmostLuckyNumbersDivOne
SRM 510 · 2010-11-01 · by Vasyl[alphacom] · Simple Search, Iteration
Class Name: TheAlmostLuckyNumbersDivOne
Return Type: long
Method Name: find
Arg Types: (long long, long long)
Problem Statement

Problem Statement

John and Brus believe that the digits 4 and 7 are lucky and all others are not. According to them, an almost lucky number is a number that contains at most one non-lucky digit in its decimal representation. Return the total number of almost lucky numbers between a and b, inclusive.

Constraints

  • a will be between 1 and 10^16, inclusive.
  • b will be between a and 10^16, inclusive.
Examples
0)
4
7
Returns: 4

All numbers between 4 and 7 are almost lucky.

1)
8
19
Returns: 4

Numbers 8, 9, 14 and 17 are almost lucky.

2)
28
33
Returns: 0

No almost lucky numbers here.

3)
12345678900
98765432100
Returns: 91136
4)
64
86
Returns: 13

Submissions are judged against all 90 archived test cases, of which 5 are shown here. Case numbers match the judge’s.

Coding Area

Language: C++17 · define a public class TheAlmostLuckyNumbersDivOne with a public method long long find(long long a, long long b) · 90 test cases · 2 s / 256 MB per case

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