Top of a Digit Pyramid

Easy

The string digits consists of digits. A pyramid is built from it: each new row is one digit shorter, and each of its digits is the last digit of the sum of two neighboring digits in the row before (that is, the sum modulo 10). Rows are built until a row has exactly two digits. Return True if those two digits are equal, and False otherwise.

Example 1

digits="5146" → False

5146 → 650 (5+1, 1+4, 4+6=10 → 0) → 15. The digits 1 and 5 differ.

Example 2

digits="282" → True

282 → 00 (2+8=10 → 0, 8+2=10 → 0). Both digits are zero.

Constraints

3 ≤ len(digits) ≤ 100
digits contains only digits

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Topics

Math String Combinatorics Number Theory Simulation

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Input

digits="5146"

Expected

False

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