21459_Semi-primeH-numbers

2022-5-16 18:19| 发布者: Hocassian| 查看: 39| 评论: 0|原作者: 肇庆学院ACM合集

摘要:
C:\Users\Administrator\Downloads\2019-10-12-10-14-4-89505283161500-Problem List-采集的数据-后羿采集器.html

Pro.ID

21459

Title

Semi-prime H-numbers

Title链接

http://10.20.2.8/oj/exercise/problem?problem_id=21459

AC

23

Submit

56

Ratio

41.07%

时间&空间限制

  • Time Limit: 300/100 MS (Java/Others)     Memory Limit: 65536/65536 K (Java/Others)
  • 描述

    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-numbers. For this problem we pretend that these are the only numbers. The H-numbers are closed under multiplication.

    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-numbers in only one way: 1 × h. The rest of the numbers are H-composite.

    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-primes. The two H-primes may be equal or different. In the example above, all five numbers are H-semi-primes. 125 = 5 × 5 × 5 is not an H-semi-prime, because it's the product of three H-primes.

    输入

    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.

    输出

    Description

    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-numbers. For this problem we pretend that these are the only numbers. The H-numbers are closed under multiplication.

    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-numbers in only one way: 1 × h. The rest of the numbers are H-composite.

    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-primes. The two H-primes may be equal or different. In the example above, all five numbers are H-semi-primes. 125 = 5 × 5 × 5 is not an H-semi-prime, because it's the product of three H-primes.

    Input

    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.

    Output

    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

    Sample Output

    21 0
    85 5
    789 62

    Source

    样例输入

    21
    85
    789
    0

    样例输出

    21 0
    85 5
    789 62

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