AOC2502 ;; 2025 Day 2

T1  ;;TEST DATA 1;;
    ;11-22,95-115,998-1012,1188511880-1188511890,222220-222224,1698522-1698528,446443-446449,38593856-38593862,565653-565659,824824821-824824827,2121212118-2121212124
    ;;ENDS;;

DOIT(dataset,task,debug)
    N data,tsStart
    S debug=+$G(debug),task=$S(task=2:2,1:1) 
    I dataset=1 D LOAD^AOCBASE(2025,2,.data)
    I dataset=0 D LOADTD^AOCBASE("T1",$T(+0),.data)
    D TIMER^AOCBASE("START")
    D TASK(task,.data,debug)
    D TIMER^AOCBASE("STOP")
    Q

TASK(task,data,debug)
    N res S res=0
    N rangeId F rangeId=1:1:$L(data(1),",") D 
    .N range,to,from
    .S range=$P(data(1),",",rangeId)
    .S from=$P(range,"-",1)
    .S to=$P(range,"-",2)
    .W:debug rangeId,?10,from,?25,to,!
    .N prodCode
    .F prodCode=from:1:to D
    ..I task=1 D
    ...N p1,p2
    ...S p1=$E(prodCode,1,($L(prodCode)/2))
    ...S p2=$E(prodCode,$L(prodCode)/2+1,$L(prodCode))
    ...I p1'=p2 Q
    ...W:debug ?40,"Invalid ID:"_prodCode,!
    ...S res=res+prodCode
    ..I task=2 D
    ...Q:'$$RESCHK(prodCode,debug)
    ...W:debug ?40,"Invalid ID:"_prodCode,!
    ...S res=res+prodCode
    W "Answer is "_res,!
    Q

RESCHK(prodCode,debug)
    ;Checks to see if a number of recurring substrings matches the product code. Largest to smallest.
    N split,isRecur S isRecur=0
    W:debug "Code: "_prodCode_" [Len: "_$L(prodCode)_"]",!
    F split=($L(prodCode)\2):-1:1 D     ;Start halfway and then work out, integer divide here as 9/2 is not a valid split
    .Q:$L(prodCode)#split'=0            ;No point in carrying on if there is a remainder, it won't be recursive
    .Q:isRecur                          ;We already know the answer is recursive
    .N count S count=$L(prodCode)/split
    .N test S test=$E(prodCode,1,split)
    .W:debug ?25,"Split point:"_$J(split,3)_" | Count:"_$J(count,3)_" | Test String: "_test,!
    .N matchExp S matchExp=count_""""_test_""""     ;count("test"), e.g. 3("123") to check match with 123123123
    .S isRecur=prodCode?@(matchExp)     ;Indirectly pattern match [match prodCode with the pattern defined in matchExp]
    Q isRecur