UVa 136 Ugly Numbers (数论)

136 - Ugly Numbers

Time limit: 3.000 seconds

http://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&category=24&page=show_problem&problem=72

Ugly numbers are numbers whose only prime factors are 2, 3 or 5. The sequence

1, 2, 3, 4, 5, 6, 8, 9, 10, 12, 15, ...

shows the first 11 ugly numbers. By convention, 1 is included.

Write a program to find and print the 1500'th ugly number.

Input and Output

There is no input to this program. Output should consist of a single line as shown below, with <number> replaced by the number computed.

Sample output

The 1500'th ugly number is <number>.

可以用暴力先把答案算出来。

或者，用2,3,5来拼凑。

完整代码：

/*0.009s*/

#include <cstdio>

int main(void)
{
	puts("The 1500'th ugly number is 859963392.");
	return 0;
}