往上重複數 (13659)

C2=IF(B2=B3,"",ROW(A1)-LOOKUP(1,0/(B$1:B1<>B2),ROW($1:1))+1)

另解=IF(B2=B3,"",COUNTIF(B$2:B2,B2)-SUMIF(B$1:B1,B2,C$1))



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