gNumbers
Time limit5sMemory limit512 MB
Two players alternately remove every copy of one prime factor from the current number, and whoever faces a number whose digit sum is 1 or prime loses.
- Level
Medium7 of 10
- Topics
- Game theory, Number theory, Math
- Solved
- No attempts yet
Problem
Googlers love numbers, and they love games built on numbers even more. Two Googlers, Laurence and Seymour, invented a two player game around gNumbers. A number is a gNumber when the sum of its digits has no positive divisor other than 1 and itself. By that definition 1 is a gNumber.
The game runs like this. Someone who is not playing picks a starting number . The two players then alternate turns. On a turn the player checks whether the current number is a gNumber. If it is, that player loses at once. Otherwise the player picks a prime factor of and divides by repeatedly until no longer divides it. For example, with a current number of 72 the player can pick 2 and divide down to 9, or pick 3 and divide down to 8. The result of the division becomes the new current number, and the other player takes a turn.
Laurence always moves first, and he hates to lose. Given , determine which player wins when both play optimally.
Input
The first line contains the number of test cases . Each of the next lines contains one starting number .
Output
For each test case, print one line in the form "Case #x: y", where x is the test case number starting from 1 and y is the winner's name, either Laurence or Seymour.
Constraints
Hint
For the digit sum is 2, and 2 has no positive divisor other than 1 and itself, so 2 is already a gNumber. Laurence loses immediately and Seymour wins. The same holds for .
For the digit sum is 4, and 4 has the positive divisor 2 besides 1 and itself, so 4 is not a gNumber. The only prime factor of 4 is 2, so Laurence must pick 2 and divide until 1 is left. Seymour then starts his turn on 1, which is a gNumber, so Seymour loses and Laurence wins.