Factoring Large Numbers

Time Limit:  1 s      Memory Limit:   128 MB
Submission:38     AC:23     Score:98.72


One of the central ideas behind much cryptography is that factoring large numbers is computationally
intensive. In this context one might use a 100 digit number that was a product of two 50 digit prime
numbers. Even with the fastest projected computers this factorization will take hundreds of years.
You don’t have those computers available, but if you are clever you can still factor fairly large numbers.


The input will be a sequence of integer values, one per line, terminated by a negative number. The
numbers (other than the terminator) will be greater than 0 and less than 262 .


Each positive number from the input must be factored and all factors (other than 1) printed out. The
factors must be printed in ascending order with 4 leading spaces preceding a left justified number, and
followed by a single blank line.


90 1234567891 18991325453139 12745267386521023 -1
2 3 3 5 1234567891 3 3 13 179 271 1381 2423 30971 411522630413


19 June, 2011 - Waterloo local contest