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POA way of checking if the digits of num1 are the digits in num2 without checking each digit?
 

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  1. POA way of checking if the digits of num1 are the digits in num2 without checking each digit?
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    <p>Lets say I have guessed a lottery number of: </p> <blockquote> <p>1689</p> </blockquote> <p>And the way the lottery works is, the order of the digits don't matter as long as the digits match up 1:1 with the digits in the actual winning lottery number.</p> <p>So, the number 1689 would be a winning lottery number with: </p> <blockquote> <p>1896, 1698, 9816, etc..</p> </blockquote> <p>As long as each digit in your guess was present in the target number, then you win the lottery.</p> <p>Is there a mathematical way I can do this?</p> <p>I've solved this problem with a O(N^2) looping checking each digit against each digit of the winning lottery number (separating them with modulus). Which is fine, it works but I want to know if there are any neat math tricks I can do.</p> <p>For example, at first... I thought I could be tricky and just take the sum and product of each digit in both numbers and if they matched then you won.</p> <p>^ Do you think that would work?</p> <p><strike>However, I quickly disproved this when I found that lottery guess: 222, and 124 have the different digits but the same product and sum.</strike></p> <p>Anyone know any math tricks I can use to quickly determine if the digits in num1 match the digits in num2 regardless of order?</p>
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    1. USinspectorG4dget
    1. USKingNestor
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    1. CO2+2+2 = 6, 1+2+4 = 7, so they don't have the same sum. I think this sum/product method may actually work as long as the number of digits in each number is equal.
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      1. USMahlerFive
    2. COWell, the product trick will be defeated by zeros; 0123 and 0222 have the same product and sub.
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      1. USDaniel LeCheminant
    3. COAlso, if both numbers are the same except for 3 digits, one containing 449 and the 368, they'll both have the same product and sum (since those numbers both have the same product and sum, and both + and * are commutative)
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      1. POA way of checking if the digits of num1 are the digits in num2 without checking each digit?
      1. USDaniel LeCheminant
 

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