题目：
Description
Mike is very lucky, as he has two beautiful numbers, 3 and 5. But he is so greedy that he wants infinite beautiful numbers. So he declares that any positive number which is dividable by 3 or 5 is beautiful number. Given you an integer N (1 <= N <= 100000), could you please tell mike the Nth beautiful number?
Input
The input consists of one or more test cases. For each test case, there is a single line containing an integer N.
Output
For each test case in the input, output the result on a line by itself.
Sample Input
1
2
3
4
Sample Output
3
5
6
9
解题思路：
采用预处理的方法，将可以被3和5整除的数按顺序放入数组中，下标便是顺序，对于输入的每个test case 输出对应的数组中的元素
细节处理：
预处理时，要处理大于100000个元素，
代码：
#include <iostream>
#include<cmath>
#include<vector>
using namespace std;
int main()
{
int x[250000];
int i,num=1;
for(i=1;i<500000;i++)
{
if(i%3==0||i%5==0) { x[num]=i; num++;}
if(num==199999) break;
}
int c;
while(cin>>c)
{
cout<<x[c]<<endl;
}
return 0;
}