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Baltic Way
2015 Baltic Way
8
8
Part of
2015 Baltic Way
Problems
(1)
Combinatorics
Source: Baltic Way 2015
11/8/2015
With inspiration drawn from the rectilinear network of streets in New York , the Manhattan distance between two points
(
a
,
b
)
(a,b)
(
a
,
b
)
and
(
c
,
d
)
(c,d)
(
c
,
d
)
in the plane is defined to be
∣
a
−
c
∣
+
∣
b
−
d
∣
|a-c|+|b-d|
∣
a
−
c
∣
+
∣
b
−
d
∣
Suppose only two distinct Manhattan distance occur between all pairs of distinct points of some point set. What is the maximal number of points in such a set?
combinatorics