Solve With Force!
I finally got around to completing #1 on the GLAT today. The google folks really need to be more specific about what they want. Number one basically says: Solve this cryptic equation, noting however, that values for m and e are interchangeable. The equation is: WWWDOT-GOOGLE=DOTCOM It does not specify weather or not a number can appear more than once..(i.e..can T=O?). If you were to try solving this by hand, you would have to make such conjectures as: If two numbers are subtracrted to form a third number comprised of the same number of digits as the original two numbers, then 1st Digit in the second number subtracted from the 1st digit in the first number will equal the 1st digit in the third number. This however, is not nesessarily true, but one can solve this in this manner. #1 also states that no leading zeros are allowed. This means that W can not be 0, D can not be 0, G cannot be 0, and logically, O cannot be 0. Solving this by hand using the method I stated above would lead you to things such as: w=2*O, T=O….and equal values for e and m also mean they are interchangable….so T=2*M, w=4*M…then M is 1 or 2, and w is 4 or 8, respectively. Now, If google did specify that no digit could be repeated, then the only sane way to solve this would be via a computer program, which I also did. I made the brute-force program in php (ran it from command line) and it gave me 144 permutations…2 of which had unique digits…the only difference being interchanged valued for m and e. here they are:
777589-188103=589486
777589-188106=589483
That is probably what google is looking for, but they really should specify. The Brute Force Program took only 126 seconds to run, all the possible answers it generated can be found here.