http://acm.timus.ru/problem.aspx?space=1&num=1132 题意: 求 x^2 ≡ n mod p  p是质数 的 解 本题中n>=1 特判p=2,接下来求当p是奇素数时的解 引理1: 引理2:方程有解当且仅当 定理: 设a满足 不是模p的二次剩余, 即无解, 那么是二次剩余方程的解 #include<cstdio> #include<cstdlib> #include<algorithm> using namesp…

不理解,背板子 #include<cstdio> using namespace std; int Pow(int a,int b,int p) { ; ) ) res=1LL*a*res%p; return res; } bool Legendre(int a,int p) { >>,p)==; } void modsqr(int a,int p) { int x; int i,k,b; ) x=a%p; ==) x=Pow(a,p+>>,p); else { ;Le…

题意: 求\(x^2 \equiv a \mod p\) 的所有整数解 思路: 二次剩余定理求解. 参考: 二次剩余Cipolla's algorithm学习笔记 板子: //二次剩余,p是奇质数 ll ppow(ll a, ll b, ll mod){ ll ret = 1; a = a % mod; while(b){ if(b & 1) ret = ret * a % mod; a = a * a % mod; b >>= 1; } return ret; } struct TT…

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…

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…

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…

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…