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ROSECODE 559

Balanced numbers revisited

C_K_Yang · Programming ·

A positive integer with k (decimal) digits is called balanced if its first k2 digits sum to the same value as its last k2 digits, where x, pronounced ceiling of x, is the smallest integer x, thus π=4 and 5=5.

For example, 77, 101, 13722, and 585774 are balanced numbers.

Find the number and the sum of all balanced numbers n for 0<n111111 and give your answer modulo 1000000007

Answer format: count,sum(both modulo 1000000007)

You are given: 634521,744405873 for a threshold of 12345678


[My timing: 1 s]