Skip to article frontmatterSkip to article content
Site not loading correctly?

This may be due to an incorrect BASE_URL configuration. See the MyST Documentation for reference.

Suppose there are nn distinct numbers x1,…,xnx_1,\ldots, x_n, and y1,…,yny_1, \ldots, y_n is a random permutations of them. If ∃k\exists k such that yk<yi,∀1≤i<ky_k<y_i, \forall 1\le i<k, then we say that yky_k is a record (we always count y1y_1 as a record). What is the expected number of records in y1,…,yny_1, \ldots, y_n?

See my neat solution here.