This is a harder version of KBB3 Problem 4.
Suppose $n$ is an odd positive integer. Given an $n \times n$ chessboard where each cell is colored black or white. At any step, we are allowed to pick any cell and flip the colors of the cells that are in the same row or the same column as that cell. Prove or disprove: no matter what the initial coloring is, we can always get an all-white board?
Showing posts with label reversible. Show all posts
Showing posts with label reversible. Show all posts
Monday, September 21, 2009
Thursday, September 17, 2009
KBB3 Problem 4
Given a 3x3 chessboard where each cell is colored black or white. At any step, we are allowed to pick any column or any row and flip all the cell colors in that column or row. Prove or disprove: no matter what the initial coloring is, we can always get an all-white board?
Labels:
Combinatorics,
commutative,
comparing sets,
invariant,
inverse,
johan gunardi,
KBB,
KBB3,
reversible,
Solved,
step
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