I have alphabet array 24 character: “A B C D E F G H I J K L M N O P Q R S T U V W X”
I want collect all case with: 3 unique characters.
First case: ABC, DEF, GHI, JKL, MNO, PQR, STU, VWX
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I have alphabet array 24 character: “A B C D E F G H I J K L M N O P Q R S T U V W X”
I want collect all case with: 3 unique characters.
First case: ABC, DEF, GHI, JKL, MNO, PQR, STU, VWX
There’s a 1:1 relationship between the permutations of the letters of the alphabet and your sets lists. Basically, once you have a permutation of the alphabet, you just have to call
array_chunkto get the sets.Now, 24! of anything (that is 620448401733239439360000) will never fit in memory (be it RAM or disk), so the best you can do is to generate a number
nbetween1and24!(the permutation number) and then generate such permutation. For this last step, see for example Generation of permutations following Lehmer and Howell and the papers there cited.