A Survo puzzle is a kind of logic puzzle presented (in April 2006) and studied by Seppo Mustonen. The name of the puzzle is associated with Mustonen's Survo system, which is a general environment for statistical computing and related areas.
In a Survo puzzle, the task is to fill an m × n table with integers 1, 2, ..., m·n so that each of these numbers appears only once and their row and column sums are equal to integers given on the bottom and the right side of the table. Often some of the integers are given readily in the table in order to guarantee uniqueness of the solution and/or for making the task easier.
To some extent, Survo puzzles resemble Sudoku and Kakuro puzzles. However, numbers used in the solution are not restricted to 1, 2, ..., 9 and the size of puzzle grid is typically very small. Solving Survo puzzles is also related to making of magic squares.
The degree of difficulty in solving Survo puzzles is strongly varying. Easy puzzles, meant for school children, are pure exercises in addition and subtraction, while more demanding ones require also good logic reasoning. The hardest Survo puzzles cannot be solved without computers.
Certain properties of the Survo system like editorial computing and the COMB operation, making e.g. restricted integer partitions, support solving of Survo puzzles.
Survo puzzles have been published regularly in Finland by Ilta-Sanomat and the scientific magazine of the University of Helsinki from September 2006. Solving of Survo puzzles was one of the three main topics in the national entrance examination of the Finnish universities in computer science (2009).
Famous quotes containing the word puzzle:
“What are you now? If we could touch one another,
if these our separate entities could come to grips,
clenched like a Chinese puzzle . . . yesterday
I stood in a crowded street that was live with people,
and no one spoke a word, and the morning shone.
Everyone silent, moving. . . . Take my hand. Speak to me.”
—Muriel Rukeyser (19131980)