题意 ABC的位置关系只有三种可能: 1.在一条直线上,输出TOWARDS A--B--C 2.AB 和BC垂直,B为直角顶点,AB左侧是C,输出LEFT C--B | A 3.AB 和BC垂直,B为直角顶点,AB右侧是C,输出RIGHT B --C | A 给你ABC三点的坐标,求背朝A,站在B点,往C走要前进还是左转还是右转. 分析 假定ABC的坐标:A(xa,ya),B(xb,yb),C(xc,yc),粗体表示向量. BA为(x1,y1)=(xa-xb,ya-yb) BC为(x2,y2)=…

A. Where do I Turn? 叉积判断. B. Effective Approach 记录位置. C. Flying Saucer Segments 假设有\(n\)个人,那么\(1\)要移动的话,需要先移动前\(n-1\)个人. 有点类似于汉诺塔问题,写出递推式后矩阵+快速幂计算. D. Naughty Stone Piles \(k\)叉树,权值越小的深度越大,每种\(k\)做一次即可. E. Anniversary Fibonacci数列性质\[gcd(F_a, F_b)=F_{…

Space Ant Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 3840   Accepted: 2397 Description The most exciting space discovery occurred at the end of the 20th century. In 1999, scientists traced down an ant-like creature in the planet Y19…

Space Ant Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 3967   Accepted: 2489 Description The most exciting space discovery occurred at the end of the 20th century. In 1999, scientists traced down an ant-like creature in the planet Y19…

D. Bicycle Race 题目连接: http://www.codeforces.com/contest/659/problem/D Description Maria participates in a bicycle race. The speedway takes place on the shores of Lake Lucerne, just repeating its contour. As you know, the lake shore consists only of s…

TOYS   Description Calculate the number of toys that land in each bin of a partitioned toy box. Mom and dad have a problem - their child John never puts his toys away when he is finished playing with them. They gave John a rectangular box to put his…

POJ2318 本题需要运用to left test不断判断点处于哪个分区,并统计分区的点个数(保证点不在边界和界外),用来做叉积入门题很合适 //计算几何-叉积入门题 //Time:157Ms Memory:828K #include<iostream> #include<cstring> #include<cstdio> #include<algorithm> using namespace std; #define MAXN 5005 struct P…

Text I was having dinner at a restaurant when Tony Steele came in. Tony worked in a layer's office years ago, but he is now working at a bank. He gets a good salary, but he always borrows money from his friends and never pays it back. Tony saw me and…

webRTC支持点对点通讯,但是webRTC仍然需要服务端:  . 协调通讯过程中客户端之间需要交换元数据,    如一个客户端找到另一个客户端以及通知另一个客户端开始通讯.  . 需要处理NAT(网络地址转换)或防火墙,这是公网上通讯首要处理的问题.    所以我们需要了解服务端相关的知识:信令.Stun.trun.ice. 一.什么是信令 信令就是协调通讯的过程,为了建立一个webRTC的通讯过程,客户端需要交换如下信息:  . 会话控制信息,用来开始和结束通话,即开始视频.结束视频这些操作…

原题:  Turn the pokers       思路:假设正面为0,反面为1.牌就像这样 000000....... .考虑到假如可以实现最终反面个数为m, 牌共n张, 则这n张排任取m个为反面其余都为正面的状况都能实现.于是转化为考虑最终可能出现1的个数的集合有哪些.       因为可能的个数集合是连续的(在最大最小值之内相差2的都可能), 所以每一次翻转之后的上下限都可以根据上一次所得的上下限推出.       最后算排列组合的适合需要用到组合数递推公式和费马小定理推论\( a^{p…