15 May 2021

• 00:1400:14, 15 May 2021 diff hist +534 N 1998 IMO Shortlist Problems/C4 Created page with "If A is a permutation of 1, 2, 3, ... , n and B is a subset of {1, 2, ... , n}, then we say that A splits B if we can find three elements of A such that the middle element doe..." current
• 00:1300:13, 15 May 2021 diff hist +285 N 1998 IMO Shortlist Problems/C3 Created page with "The numbers from 1 to 9 are written in an arbitrary order. A move is to reverse the order of any block of consecutive increasing or decreasing numbers. For example, a move cha..." current
• 00:0800:08, 15 May 2021 diff hist +580 N 1998 IMO Shortlist Problems/C2 Created page with " n is a fixed positive integer. An odd n-admissible sequence a_1, a_2, a_3, ... satisfies the following conditions: 1 : a_1 = 1. 2 : a_2k = a_2k-1 + 2 or a_2k-1 + n 3 : a_2k+..." current
• 00:0500:05, 15 May 2021 diff hist +195 N 1998 IMO Shortlist Problems/C1 Created page with " An m x n array of real numbers has the sum of each row and column integral. Show that each non-integral element x can be changed to [x] or [x] + 1, so that the row and column..."