HMMT 二月 2008 · 冲刺赛 · 第 35 题
HMMT February 2008 — Guts Round — Problem 35
题目详情
英文原题
- NUMB3RS. The RSA Factoring Challenge, which ended in 2007, challenged computational mathematicians to factor extremely large numbers that were the product of two prime numbers. The largestnumber successfully factored in this challenge was RSA-640, which has 193 decimal digits and carrieda prize of 30 , 000, and contains N decimal digits.
Your task is to submit a guess for N . Only the team(s) that have the closest guess(es) receives points.
⌈ ⌉
If k teams all have the closest guesses, then each of them receives points.20 k
解析
英文解析
- NUMB3RS. The RSA Factoring Challenge, which ended in 2007, challenged computational mathematicians to factor extremely large numbers that were the product of two prime numbers. The largestnumber successfully factored in this challenge was RSA-640, which has 193 decimal digits and carrieda prize of 30 , 000, and contains N decimal digits.
Your task is to submit a guess for N . Only the team(s) that have the closest guess(es) receives points.
⌈ ⌉
If k teams all have the closest guesses, then each of them receives points.20
Answer: 212 For more information, see the Wikipedia entry at http://en.wikipedia.org/wiki/k
RSA_Factoring_Challenge .
RSA-640 was factored in November 2005, and the effort took approximately 30 2.2GHz-Opteron-CPUyears over five months of calendar time.