原题链接 http://projecteuler.net/problem=32

Pandigital products

We shall say that an n-digit number is pandigital if it makes use of all the digits 1 to n exactly once; for example, the 5-digit number, 15234, is 1 through 5 pandigital.

The product 7254 is unusual, as the identity, 39 * 186 = 7254, containing multiplicand, multiplier, and product is 1 through 9 pandigital.

Find the sum of all products whose multiplicand/multiplier/product identity can be written as a 1 through 9 pandigital.
HINT: Some products can be obtained in more than one way so be sure to only include it once in your sum.

全位数乘积
如果一个n位数恰好使用1到n各一次，我们称这个数为全位数；例如，5位数，15234，是一个1到5的全位数。

乘积7254不寻常，对于恒等式 39 * 186 = 7254，包括被乘数，乘数，乘积，正好是一个1到9的全位数

求所有满足被乘数，乘数，乘积这个恒等式是从1到9的全位数这个条件的乘积的和。
提示：有些乘积可以有不只一种形式，要确保只计算一次。
解法：
这题没什么好说的。