TheLargestLuckyNumber
SRM 403 · 2008-05-29 · by Vasyl[alphacom]
SRM 403 · 2008-05-29 · by Vasyl[alphacom] · Simulation
Problem Statement
Problem Statement
John thinks 4 and 7 are lucky digits, and all other digits are not lucky. A lucky number is a number that contains only lucky digits in decimal notation.
You are given an
Constraints
- n will be between 4 and 1,000,000, inclusive.
Examples
0)
100 Returns: 77
77 is the largest lucky number that is not greater than 100.
1)
75 Returns: 74
74 is the lucky number that immediately precedes 77.
2)
5 Returns: 4
The smallest lucky number is 4.
3)
474747 Returns: 474747
n is a lucky number.
4)
1000000 Returns: 777777
Submissions are judged against all 49 archived test cases, of which 5 are shown here. Case numbers match the judge’s.
Coding Area
Language: C++17 · define a public class TheLargestLuckyNumber with a public method int find(int n) · 49 test cases · 2 s / 256 MB per case