[理工] DS time complexity
T(n) = T(n-1) + 1/n , T(1) = 1
(sol)
T(n) = T(n - 1) + 1 / n
= [T(n - 2) + 1 / (n - 1)] + 1 / n
.
.
.
.
= T(1) + 1 / 2 + 1 / 3 + ...... + 1 /(n - 1) + 1 / n
(answer)
= O(log n)
↑ 怎麼轉換的?
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