Add problem descritpion for FirstUniqueCharacterInString

Put problem source URL above package declaration

Add missing values at DiagonalDifference

Add problem description at DiagonalDifference

Put problem sourcle URL before package declaration at DiagonalDifference

Add missing values at CompareTheTriplets description

Add missing values at CompareTheTriplets description

Add missing constraints at CompareTheTriplets

Add problem description at CompareTheTriplets

Put problem source before package declaration at CompareTheTriplets

Add constraints and outputformat at BirthdayCakeCandle

Add missing values at problem description at BirthdayCakeCandle

Add problem description at BirthdayCakeCandle

Put problem source ULR before package declaration at BirthdayCakeCandles

Add problem description at FidnTheDifference