做个外贸的网站不懂英语咋做互联网营销模式有哪些
题目:小明向他的女朋友仙仙求婚,在求婚戒指上刻了一个大大的爱心。仙仙看到爱心想考验一下小明,出了一道题。方程(x2+y2−1)2−x2y2=0,这个点在这个爱心里面的概率是多少,精确到0.1(小数点后保留一位小数,比如0.1, 0.2等)
#include <iostream>
#include <math.h>using namespace std;/*生成标准正态分布随机数*/
double gaussRand(){static double V1,V2,S;static int phase=0;double X;if(phase==0){do{double U1=(double)rand()/RAND_MAX;double U2=(double)rand()/RAND_MAX;V1=2*U1-1;V2=2*U2-1;S=V1*V1+V2*V2;}while(S>=1||S==0);X=V1*sqrt(-2*log(S)/S);}elseX=V2*sqrt(-2*log(S)/S);phase=1-phase;return X;
}/*将随机值从正态分布N(0,1)转化到高斯分布N(mu,sigma)*/
double gaussValue(double val,double mu,double sigma)
{return mu+sigma*val;
}
/*判断随机值是否在曲线内*/
bool isInside(double x,double y)
{ double x2=x*x;double y2=y*y;double temp=x2+y2-1;return (temp*temp-x2*y2)>0?false:true;
}
/*模拟*/
double learnCurve(double mu1,double sigma1,double mu2,double sigma2)
{int n=10000;//模拟次数int count=0;int i=n;while(i-->0){double x=gaussValue(gaussRand(),mu1,sigma1);double y=gaussValue(gaussRand(),mu2,sigma2);if(isInside(x,y))count++;}return (double) count/n;
}int main()
{double mu1,mu2,sigma1,sigma2;cin>>mu1>>sigma1>>mu2>>sigma2;double res=learnCurve(mu1,sigma1,mu2,sigma2);printf("%.1f\n",res);return 0;
}
- 1
- 2
- 3
- 4
- 5
- 6
- 7
- 8
- 9
- 10
- 11
- 12
- 13
- 14
- 15
- 16
- 17
- 18
- 19
- 20
- 21
- 22
- 23
- 24
- 25
- 26
- 27
- 28
- 29
- 30
- 31
- 32
- 33
- 34
- 35
- 36
- 37
- 38
- 39
- 40
- 41
- 42
- 43
- 44
- 45
- 46
- 47
- 48
- 49
- 50
- 51
- 52
- 53
- 54
- 55
- 56
- 57
- 58
- 59
- 60
- 61
- 62
- 63
- 64
- 65
- 66
- 67
- 68
- 69

- 1
- 2
- 3
- 4
- 5
- 6
- 7
- 8
- 9
- 10
- 11
- 12
- 13
- 14
- 15
- 16
- 17
- 18
- 19
- 20
- 21
- 22
- 23
- 24
- 25
- 26
- 27
- 28
- 29
- 30
- 31
- 32
- 33
- 34
- 35
- 36
- 37
- 38
- 39
- 40
- 41
- 42
- 43
- 44
- 45
- 46
- 47
- 48
- 49
- 50
- 51
- 52
- 53
- 54
- 55
- 56
- 57
- 58
- 59
- 60
- 61
- 62
- 63
- 64
- 65
- 66
- 67
- 68
- 69
参考:
http://blog.csdn.net/shijing_0214/article/details/60465542
http://www.cnblogs.com/tsingke/p/6194737.html