The Circumference of the Circle Time Limit: 2 Seconds      Memory Limit: 65536 KB To calculate the circumference of a circle seems to be an easy task - provided you know its diameter. But what if you don't? You are given the cartesian coordinates of…

  ZOJ Problem Set - 1090 The Circumference of the Circle Time Limit: 2 Seconds      Memory Limit: 65536 KB To calculate the circumference of a circle seems to be an easy task - provided you know its diameter. But what if you don't? You are given the…

原题链接 题目大意:已知三角形的三个顶点坐标,求其外接圆的周长. 解法:刚看到这道题时,马上拿出草稿纸画图,想推导出重心坐标,然后求出半径,再求周长.可是这个过程太复杂了,写到一半就没有兴致了,还是求助于Google.在Wiki百科找到一个已知三条边长度,求外接三角形周长的算法,diameter = abc/2*(sqrt(s(s-a)(s-b)(s-c)),s=(a+b+c)/2.问题瞬间简化了,求两点距离是很方便的一件事,然后套用这个公式就可以了. 参考代码: #include<iostre…

做题回顾:用到海伦公式,还有注意数据类型,最好统一 p=(a+b+c)/2; s=sqrt(p*(p-a)*(p-b)*(p-c));//三角形面积,海伦公式 r=a*b*c/(4*s);//这是外接圆的半径 /* Sample Input 0.0 -0.5 0.5 0.0 0.0 0.5 0.0 0.0 0.0 1.0 1.0 1.0 5.0 5.0 5.0 7.0 4.0 6.0 0.0 0.0 -1.0 7.0 7.0 7.0 50.0 50.0 50.0 70.0 40.0 60.0 0…

计算几何模板 #include<stdio.h> #include<string.h> #include<stdlib.h> #include<math.h> #include<algorithm> ; const double pi = acos(-1.0); int dcmp(double x) { ; : ; } struct Point { double x, y; Point() { x = y = ; } Point(double a…

Description To calculate the circumference of a circle seems to be an easy task - provided you know its diameter. But what if you don't?         You are given the cartesian coordinates of three non-collinear points in the plane.         Your job is t…

Problem ATriangle Fun Input: Standard Input Output: Standard Output In the picture below you can see a triangle ABC. Point D, E and F divides the sides BC, CA and AB into ratio 1:2 respectively. That is CD=2BD, AE=2CE and BF=2AF. A, D; B, E and C, F…

POJ 2251 题目大意: 给出一三维空间的地牢,要求求出由字符'S'到字符'E'的最短路径,移动方向可以是上,下,左,右,前,后,六个方向,每移动一次就耗费一分钟,要求输出最快的走出时间.不同L层的地图,相同RC坐标处是相连通的.(.可走,#为墙) 解题思路:从起点开始分别往6个方向进行BFS(即入队),并记录步数,直至队为空.若一直找不到,则困住. /* POJ 2251 Dungeon Master --- 三维BFS(用BFS求最短路) */ #include <cstdio> #i…

The Center of Gravity Time Limit: 3000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 3971    Accepted Submission(s): 2280 Problem Description Everyone know the story that how Newton discovered the Universal Gr…

[POJ 2195] Going Home(KM算法求最小权匹配) Going Home Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 20303   Accepted: 10297 Description On a grid map there are n little men and n houses. In each unit time, every little man can move one unit ste…