Solutions for NOIP 2009: Password Decryption, Inverse GCD-LCM, Trade Profit, and Target Sudoku
Problem 1: Decrypting S Country's Military Cipher
Description
R and S are at war. R's spy, Xiao C, has obtained S's encryption rule: each uppercase letter maps to a unique uppercase letter (bijection). Given a known encrypted string and its original string, build the substitution table. Then translate a new intercepted encrypted string. If the ...
Posted on Mon, 05 Oct 2026 16:17:26 +0000 by justinjkiss