Created
June 14, 2016 10:33
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根據題目分析,先按照餘數分類: | |
假設答案為 N | |
mod 1,3,7,9 餘 0 ........ (1) | |
mod 2,4,5,8 餘 1 ........ (2) | |
mod 6 餘 3 .............. (3) | |
lcm(3,7,9) = 63 ......... (4), by (1) | |
lcm(2,4,5,8) = 40 ....... (5), by (2) | |
N ≡ 0 mod 63 ..... (6), by (4) | |
N ≡ 1 mod 40 ..... (7), by (5) | |
N ≡ 3 mod 6 ....... (8), by (3) | |
Solve integer m,n,l | |
N = 63m ........... (9), by (6) | |
= 40n + 1 ....... (10), by (7) | |
= 6l + 3 ........ (11), by (8) | |
63m = 60m + 3m = 6l + 3 ....... by (6),(8) | |
3m ≡ 3 mod 6 | |
3m = 3(2s+1) = 6s + 3 ≡ 3 mod 6 | |
m = 2s + 1 ........ (12) | |
63m = 63(2s+1) | |
= 126s + 63 | |
= 40(3s+1) + 6s + 23 ≡ 1 mod 40 | |
6s + 23 ≡ 1 mod 40 | |
6s + 23 = 40p + 1 ....... (13) | |
By brute force: | |
Given p = 1: | |
s = 3 ....... by (13) | |
m = 7 ....... by (12) | |
N = 63 * 7... by (6) | |
= 441 |
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