MathDB
numbers in a grid

Source: Pan-American Girls’ Mathematical Olympiad 2023 P6

August 9, 2023
gridOperations

Problem Statement

Let n2n \geq 2 be an integer. Lucia chooses nn real numbers x1,x2,,xnx_1,x_2,\ldots,x_n such that xixj1\left| x_i-x_j \right|\geq 1 for all iji\neq j. Then, in each cell of an n×nn \times n grid, she writes one of these numbers, in such a way that no number is repeated in the same row or column. Finally, for each cell, she calculates the absolute value of the difference between the number in the cell and the number in the first cell of its same row. Determine the smallest value that the sum of the n2n^2 numbers that Lucia calculated can take.