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Switzerland Contests
Switzerland - Final Round
2021 Switzerland - Final Round
7
7
Part of
2021 Switzerland - Final Round
Problems
(1)
combinatorics
Source: Switzerland Final Round 2021 P7
2/24/2021
Let
m
≥
n
m \ge n
m
≥
n
be positive integers. Frieder is given
m
n
mn
mn
posters of Linus with different integer dimensions of
k
×
l
k \times l
k
×
l
with
1
≥
k
≥
m
1 \ge k \ge m
1
≥
k
≥
m
and
1
≥
l
≥
n
1 \ge l \ge n
1
≥
l
≥
n
. He must put them all up one by one on his bedroom wall without rotating them. Every time he puts up a poster, he can either put it on an empty spot on the wall or on a spot where it entirely covers a single visible poster and does not overlap any other visible poster. Determine the minimal area of the wall that will be covered by posters.
combinatorics