Solve a math problem with PHP "There are many experts to solve, look forward to a better algorithm for the emergence of"

Http://www.111cn.net/html/00/54500_itemid_29653.html

A six-digit number, when used separately by the 2,3,4,5,6, the resulting five product is a six-digit number, and the five numbers are made up of six digits, but the order is changed!
Ask the Master to help solve!




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looks like everyone's tacitly a phenomenon.
Http://www.111cn.net/viewthread.php?tid=54377&page=5

A previous hypothesis seems to be that everyone does not consider the existence of the algorithm when this situation may be if there is any argument that this assumption does not set up or the landlord's title itself by default does not consider this assumption please the heroes to explain

If there is no argument or the topic is not clearly stated that does not consider this hypothetical algorithm design is also the problem of invalid algorithm


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Two algorithms are written:
The first is to determine whether the sum of each bit of the multiplication is equal, but not in a very efficient way.
The second algorithm is a new way of thinking, with the character reverse direction validation, because the forward will have a part of the high level of unnecessary operations. The code is concise and efficient, with code:

The first algorithm that determines the sum of the various digits:


===========================================================

The second algorithm, the character of the reverse direction query:



The first algorithm needs 440ms on my Pe2140@2.66ghz, and the second one only needs 180ms.




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I've mentioned this question before, http://www.111cn.net/bbs/thread-54377-2-1.html.

There is one way to solve this problem:
Get every bit, one bit out.
If two digits are the same, two are deleted or changed at the same time.
Like what:
' 123451 ' and ' 123456 '
If you delete or change a bit, the rest will not wait.





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for ($i = 100000; $i < 166667; $i + +)//number range
{
....
For ($ii =2 $ii <7; $ii + +)//2-6 Multiples
{
.....
For ($j =0 $j <6; $j + +)//number
{
if ( strpos $i $i $j