#include<iostream>

#include<stdlib.h>

#include<time.h>

using namespace std;

#define PI 3.1415926

int set_count(int n)

{

const int MAX = 100000;

int arr[10000];

int flag = 1, i = 0;

while (flag)

{

arr[i] = int(rand() % n);

for (int j = 0; j < i; j++)

if (arr[i] == arr[j])

flag = 0;

i++;

}

return i;

}

int evaluate_n(int n)

{

int count = 0, tem = 0;

//每个集合随机估计10次，求平均值

for (int i = 0; i < 10; i++)

{

tem = set_count(n);

count += 2 * tem*tem / PI;

}

count /= 10;

return count;

}

void main1()

{

srand((unsigned)time(NULL));

//int n=1000, i = 0;

//int count = 0,tem=0;

//for (i=0; i < 10; i++)

//{

// tem = set_count(n);

// count += 2 * tem*tem / PI;

//}

//count /= 10;

//cout << count << endl;

int n = 100;

for (int i = 0; i < 3; i++)

{

cout << "当n=" << n << "时，估计集合的势：" << evaluate_n(n) << endl;

n = n * 10;

}

system("pause");

}