题目链接:uva 10831 - Gerg's Cake 题目大意:给定a和p.p为素数,问说是否存在x,使得x2≡a%p 解题思路:勒让德记号,推断ap−12≡1%p #include <cstdio> #include <cstring> #include <algorithm> using namespace std; typedef long long ll; ll pow_mod (ll a, ll n, ll mod) { ll ans = 1; while…

UVA 10831 - Gerg's Cake 题目链接 题意:说白了就是给定a, p.问有没有存在x^2 % p = a的解 思路:求出勒让德标记.推断假设大于等于0,就是有解,小于0无解 代码: #include <stdio.h> #include <string.h> long long a, p; long long pow_mod(long long x, long long k, long long mod) { long long ans = 1; while (k…

UVA 816 - Abbott's Revenge option=com_onlinejudge&Itemid=8&page=show_problem&category=599&problem=757&mosmsg=Submission+received+with+ID+14332151" target="_blank" style="">题目链接 题意:一个迷宫,每一个点限制了从哪一方向来的.仅仅能往左右前…

题目链接:uva 11825 题意: 你是一个黑客,侵入了n台计算机(每台计算机有同样的n种服务),对每台计算机,你能够选择终止一项服务,则他与其相邻的这项服务都终止.你的目标是让很多其它的服务瘫痪(没有计算机有该项服务). 思路:(见大白70页,我的方程与大白不同) 把n个集合P1.P2.Pn分成尽量多的组,使得每组中全部集合的并集等于全集,这里的集合Pi是计算机i及其相邻计算机的集合,用cover[i]表示若干Pi的集合S中全部集合的并集,dp[s]表示子集s最多能够分成多少组,则 假设co…

UVA 12103 - Leonardo's Notebook 题目链接 题意:给定一个字母置换B.求是否存在A使得A^2=B 思路:随意一个长为 L 的置换的k次幂,会把自己分裂成gcd(L,k) 分, 而且每一份的长度都为 L / gcd(l,k).因此平方对于奇数长度不变,偶数则会分裂成两份长度同样的循环,因此假设B中偶数长度的循环个数不为偶数必定不存在A了 代码: #include <stdio.h> #include <string.h> const int N = 30…

UVA 11774 - Doom's Day 题目链接 题意:给定一个3^n*3^m的矩阵,要求每次按行优先取出,按列优先放回,问几次能回复原状 思路:没想到怎么推理,找规律答案是(n + m) / gcd(n, m),在topcoder上看到一个证明,例如以下: We can associate at each cell a base 3-number, the log3(R) most significant digits is the index of the row of the cel…

题目例如以下: The Sultan's Successors  The Sultan of Nubia has no children, so she has decided that thecountry will be split into up to k separate parts on her death andeach part will be inherited by whoever performs best at some test. Itis possible for an…

King's Cake Accepts: 967 Submissions: 1572 Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 65536/65536 K (Java/Others) Problem Description It is the king's birthday before the military parade . The ministers prepared a rectangle cake of size n×m…

UVA 11825 - Hackers' Crackdown 状态压缩 dp 枚举子集 ACM 题目地址:option=com_onlinejudge&Itemid=8&page=show_problem&problem=2925" style="color:rgb(0,136,204); text-decoration:none">11825 - Hackers' Crackdown 题意:  有一个由编号0~n-1的n台计算机组成的网络,一共…

Problem D Morley's Theorem Input: Standard Input Output: Standard Output Morley's theorem states that that the lines trisecting the angles of an arbitrary plane triangle meet at the vertices of an equilateral triangle. For example in the figure below…