AtCoder Regular Contest 060 review

Link ARC 060 top page Editorial C: Tak and Cards – 高橋君とカード Dynamic programming I could come up only full search using bit operation during the contest. But it can be solved by DP. Below is full score (Section 3.3 of editorial) implementation.

  D: Digit Sum – 桁和 I came up different approach from editorial. Let \(a_i\) be \(i\)-th digit with base \(b\). Then, $$ n = \sum_i b^i a_i  $$ $$ s = f(b, n) = \sum_i a_i  $$ applies. If we subtract these equation, we obtain $$ n – s = \sum_i (b^i – 1) a_i  $$ Both side should be integer, and right hand side […]

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