121. A number sequence
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easy - accepted / - tried
Here is a sequence:
'1'
, first number is 1'11'
, since previous number has One(1) 1'21'
, since previous number has Two(2) 1s'1211'
, since previous number has One(1) 2 and One(1) 1'111221'
, since previous number has One(1) 1, One(1) 2, Two(2) 1s'312211'
, since previous number has Three(3) 1s, Two(2) 2s, One(1) 1- ....
As explained above, the sequence is generated by counting the digits of previous number.
Please create getNthNum(n)
to return the n-th number string in the sequence, n starts from 1.