time limit per test: 0.25 sec. memory limit per test: 4096 KB
input: standard output: standard
Let phi(W) is the result of encoding for algorithm: 1. If the length of W is 1 then phi(W) is W; 2. Let coded word is W = w1w2...wN and K = N / 2 (rounded down); 3. phi(W) = phi(wNwN-1...wK+1) + phi(wKwK-1...w1). For example, phi('Ok') = 'kO', phi('abcd') = 'cdab'. Your task is to find position of letter wq in encoded word phi(W).
Given integers N, q (1 <= N <= 10^9; 1<= q <= N), where N is the length of word W.
Write position of letter wq in encoded word phi(W).
Michael R. Mirzayanov
Saratov ST team Spring Contest #1
Codeforces (c) Copyright 2010-2020 Mike Mirzayanov