题意:求${x^2} \equiv n\bmod p$ 解题关键: 定理:若$a$满足$w = {a^2} - n$是模$p$的二次非剩余,即,${x^2} = w\bmod p$无解,则${(a + \sqrt w )^{\frac{{p + 1}}{2}}}$是二次剩余方程${x^2} \equiv n\bmod p$的解. 证明: $\begin{array}{l}{x^2} \equiv {(a + \sqrt w )^{p + 1}} \equiv (a + \sqrt w ){(a…

传送门 MD写一道二次剩余的板题差点写自闭了. 我用的是cipollacipollacipolla算法. 利用的是欧拉准则来找寻一个二次非剩余类来求根. 注意这题有两个等根和模数为2的情况. 代码: #include<bits/stdc++.h> using namespace std; typedef long long ll; int T,n,mod; inline int ksm(int a,int p){int ret=1;for(;p;p>>=1,a=(ll)a*a%mo…

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…

转自:http://blog.csdn.net/doyouseeman/article/details/52033204 简介 Cipolla算法是解决二次剩余强有力的工具,一个脑洞大开的算法. 认真看懂了,其实是一个很简单的算法,不过会感觉得出这个算法的数学家十分的机智. 基础数论储备 二次剩余 首先来看一个式子x2≡n(modp),我们现在给出n,要求求得x的值.如果可以求得,n为mod p的二次剩余,其实就是n在mod p意义下开的尽方.Cipolla就是一个用来求得上式的x的一个算法.…

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…

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] = …

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…

It is possible to show that the square root of two can be expressed as an infinite continued fraction.  2 = 1 + 1/(2 + 1/(2 + 1/(2 + ... ))) = 1.414213... By expanding this for the first four iterations, we get: 1 + 1/2 = 3/2 = 1.51 + 1/(2 + 1/2) = 7…

对于同余式 \[x^2 \equiv n \pmod p\] 若对于给定的\(n, P\),存在\(x\)满足上面的式子,则乘\(n\)在模\(p\)意义下是二次剩余,否则为非二次剩余 我们需要计算的是在给定范围内所有满足条件的\(x\),同时为了方便,我们只讨论\(p\)是奇质数的情况 前置定理 \(x^2 \equiv (x+p)^2 \pmod p\) 证明:\(x^2 \equiv x^2 + 2xp + p^2 \pmod p\)显然成立 对于\(x^2 \equiv n \pmod…

Square RootWhen the square root functional configuration is selected, a simplified CORDIC algorithm isused to calculate the positive square root of the input. The input, X_IN, and the output,X_OUT, are always positive and are both expressed as either…