hello I am stuck in this problem Digit Queries.I think I need to use recursion here although not quite sure how? Which algo or technique I need to study to solve this problem? Also please share similar types of problems from other ojs.Please help me with that.
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simple constructive algorithms is enough to solve this
This string contains numbers, numbers contain digits.
Note: summary length of all n-digit numbers is easy to calculate.
So you firstly brute force the length(L) of number, where your digit took place.
Also this sum grows fast, so L < 18, so L-digit number fits in 64-bit numbers.
Then you have position of first L-digit number. Now it's easy to find in what L-digit number your digit is.
Then you have L-digit number and position of digit, you just output this digit of L-digit number.