E. Square Root of Permutation A permutation of length n is an array containing each integer from 1 to n exactly once. For example, q = [4, 5, 1, 2, 3] is a permutation. For the permutation q the square of permutation is the permutation p that p[i] = …

题目链接 \(Description\) 给定一个\(n\)的排列\(p_i\),求一个排列\(q_i\),使得对于任意\(1\leq i\leq n\),\(q_{q_i}=p_i\).无解输出\(-1\). \(1\leq n\leq10^6\). \(Solution\) 对排列\(q_i\)我们建一张图,边为\(i\to q_i\).显然这张图是由几个环构成. 发现对于\(q_{q_i}\)的图,原来\(q_i\)中的奇环它们还是类似的一个奇环,原来的偶环会分裂成两个大小相等的偶环. 所…

A permutation of length n is an array containing each integer from 1 to n exactly once. For example, q = [4, 5, 1, 2, 3] is a permutation. For the permutation q the square of permutation is the permutation p that p[i] = q[q[i]] for each i = 1... n. F…

A permutation of length n is an array containing each integer from 1 to n exactly once. For example, q = [4, 5, 1, 2, 3] is a permutation. For the permutation q the square of permutation is the permutation p that p[i] = q[q[i]] for each i = 1... n. F…

Description A permutation of length n is an array containing each integer from 1 to n exactly once. For example, q = [4, 5, 1, 2, 3] is a permutation. For the permutation q the square of permutation is the permutation p that p[i] = q[q[i]] for each i…

题目分析 我们首先模拟一下题意 假设有一个 \(q _1\) \(p\) \(a_1\) \(a_x\) \(a_{a_1}\) \(a_{a_x}\) \(q\) \(x\) \(a_1\) \(a_x\) \(a_{a_1}\) \(pos\) 1 \(x\) \(a_1\) \(a_x\) 对这个表格分析,发现,当前节点的后继为前驱的对应 如果我们对 \(i \to p_i\) 建边,模拟一下,发现 偶环是会有两个环组成,而奇环会形成一个类似于五角星的图形 于是,我们可以找出所有环,对于奇…

C. Plus and Square Root time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output ZS the Coder is playing a game. There is a number displayed on the screen and there are two buttons, ' + ' (plus) an…

A. Plus and Square Root 题目连接: http://codeforces.com/contest/715/problem/A Description ZS the Coder is playing a game. There is a number displayed on the screen and there are two buttons, ' + ' (plus) and '' (square root). Initially, the number 2 is d…

A. Plus and Square Root time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output ZS the Coder is playing a game. There is a number displayed on the screen and there are two buttons, ' + ' (plus) an…

Square root digital expansion It is well known that if the square root of a natural number is not an integer, then it is irrational. The decimal expansion of such square roots is infinite without any repeating pattern at all. The square root of two i…