MathDB
Find all possible values of

Source: Balkan MO ShortList 2009 A1

April 6, 2020

Problem Statement

Let NNN \in \mathbb{N} and xk[1,1]x_k \in [-1,1], 1kN1 \le k \le N such that k=1Nxk=s\sum_{k=1}^N x_k =s. Find all possible values of k=1Nxk\sum_{k=1}^N |x_k|