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…

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…

题目链接. 题目大意: 给定三个点,即一个任意三角形,求外接圆的周长. 分析: 外接圆的半径可以通过公式求得(2*r = a/sinA = b/sinB = c/sinC),然后直接求周长. 注意: C++AC,G++WA. #include <iostream> #include <cstdio> #include <cstring> #include <cstdlib> #include <cmath> using namespace std…

已知三点坐标,算圆面积. 使用初等几何知识,根据海伦公式s = sqrt(p(p - a)(p - b)(p - c)) 和 外接圆直径 d = a * b * c / (2s) 来直接计算. #include <iostream> #include <cstring> #include <cstdlib> #include <cstdio> #include <numeric> #include <cctype> #include…

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…

Description Given any integer 0 <= n <= 10000 not divisible by 2 or 5, some multiple of n is a number which in decimal notation is a sequence of 1's. How many digits are in the smallest such a multiple of n?   Input Each line contains a number n.   …

Given the radius and x-y positions of the center of a circle, write a function randPoint which generates a uniform random point in the circle. Note: input and output values are in floating-point. radius and x-y position of the center of the circle is…

Given the radius and x-y positions of the center of a circle, write a function randPoint which generates a uniform random point in the circle. Note: input and output values are in floating-point. radius and x-y position of the center of the circle is…