UVA11005 Semi-prime H-numbers(篩法)
Problem A: Semi-prime H-numbers
This problem is based on an exercise of David Hilbert, who pedagogically suggested that one study the theory of 4n+1 numbers. Here, we do only a bit of that.An H-number is a positive number which is one more than a multiple of four: 1, 5, 9, 13, 17, 21,... are the H
As with regular integers, we partition the H-numbers into units, H-primes, and H-composites. 1 is the only unit. An H-number h is H-prime if it is not the unit, and is the product of two H
For examples, the first few H-composites are: 5 × 5 = 25, 5 × 9 = 45, 5 × 13 = 65, 9 × 9 = 81, 5 × 17 = 85.
Your task is to count the number of H-semi-primes. An H-semi-prime is an H-number which is the product of exactly two H
Each line of input contains an H-number ≤ 1,000,001. The last line of input contains 0 and this line should not be processed.
For each inputted H-number h, print a line stating h and the number of H-semi-primes between 1 and h inclusive, separated by one space in the format shown in the sample.
Sample input
21 85 789 0
Output for sample input
21 0 85 5 789 62Don Reble