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International Contests
Austrian-Polish
1994 Austrian-Polish Competition
4
4
Part of
1994 Austrian-Polish Competition
Problems
(1)
assigned number =|i - j | when endpoints of side are P_i,P_j
Source: Austrian - Polish 1994 APMC
5/3/2020
The vertices of a regular
n
+
1
n + 1
n
+
1
-gon are denoted by
P
0
,
P
1
,
.
.
.
,
P
n
P_0,P_1,...,P_n
P
0
,
P
1
,
...
,
P
n
in some order (
n
≥
2
n \ge 2
n
≥
2
). Each side of the polygon is assigned a natural number as follows: if the endpoints of the side are
P
i
P_i
P
i
and
P
j
P_j
P
j
, then the assigned number equals
∣
i
−
j
∣
|i - j |
∣
i
−
j
∣
. Let S be the sum of all
n
+
1
n + 1
n
+
1
assigned numbers. (a) Given
n
n
n
, what is the smallest possible value of
S
S
S
? (b) If
P
0
P_0
P
0
is fixed, how many different assignments are there for which
S
S
S
attains the smallest value?
combinatorics
polygon