Survo Puzzle - Swapping Method

Swapping Method

The swapping method for solution of Survo puzzles has been created by combining the idea of the original solver program to the observation that the products of the marginal sums crudely indicate the positions of the correct numbers in the final solution. The procedure is started by filling the original table by numbers 1,2,...,m·n according to sizes of these products and by computing row and column sums according to this initial setup. Depending on how these sums deviate from the true sums, it is tried to improve the solution by swapping two numbers at a time. When using the swapping method the nature of solving Survo puzzles becomes somewhat similar to that of Chess problems. By this method it is hardly possible to verify the uniqueness of the solution.

For example, a rather demanding 4 × 4 puzzle (MD=2050)

is solved by 5 swaps. The initial setup is

and the solution is found by swaps (7,9) (10,12) (10,11) (15,16) (1,2). In the Survo system, a sucro /SP_SWAP takes care of bookkeeping needed in the swapping method.