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Problems
Contests
National and Regional Contests
Turkey Contests
Turkey MO (2nd round)
2023 Turkey MO (2nd round)
4
4
Part of
2023 Turkey MO (2nd round)
Problems
(1)
31 tuplets on a blackboard
Source: 2023 Turkey NMO 2nd Round P4
12/21/2023
Initially given
31
31
31
tuplets
(
1
,
0
,
0
,
…
,
0
)
,
(
0
,
1
,
0
,
…
,
0
)
,
…
,
(
0
,
0
,
0
,
…
,
1
)
(1,0,0,\dots,0),(0,1,0,\dots,0),\dots, (0,0,0,\dots,1)
(
1
,
0
,
0
,
…
,
0
)
,
(
0
,
1
,
0
,
…
,
0
)
,
…
,
(
0
,
0
,
0
,
…
,
1
)
were written on the blackboard. At every move we choose two written
31
31
31
tuplets as
(
a
1
,
a
2
,
a
3
,
…
,
a
31
)
(a_1,a_2,a_3,\dots, a_{31})
(
a
1
,
a
2
,
a
3
,
…
,
a
31
)
and
(
b
1
,
b
2
,
b
3
,
…
,
b
31
)
(b_1,b_2,b_3,\dots,b_{31})
(
b
1
,
b
2
,
b
3
,
…
,
b
31
)
, then write the
31
31
31
tuplet
(
a
1
+
b
1
,
a
2
+
b
2
,
a
3
+
b
3
,
…
,
a
31
+
b
31
)
(a_1+b_1,a_2+b_2,a_3+b_3,\dots, a_{31}+b_{31})
(
a
1
+
b
1
,
a
2
+
b
2
,
a
3
+
b
3
,
…
,
a
31
+
b
31
)
to the blackboard too. Find the least possible value of the moves such that one can write the
31
31
31
tuplets
(
0
,
1
,
1
,
…
,
1
)
,
(
1
,
0
,
1
,
…
,
1
)
,
…
,
(
1
,
1
,
1
,
…
,
0
)
(0,1,1,\dots,1),(1,0,1,\dots,1),\dots, (1,1,1,\dots,0)
(
0
,
1
,
1
,
…
,
1
)
,
(
1
,
0
,
1
,
…
,
1
)
,
…
,
(
1
,
1
,
1
,
…
,
0
)
to the blackboard by using those moves.
combinatorics