Problem 306. Eight Queens Solution Checker

Solution 37413

Submitted on 11 Feb 2012 by @bmtran (Bryant Tran)

Size: 32
Leading solution size is 23.

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5 Comments

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Steve Eddins on 11 Feb 2012

Doesn't this kind of trick get boring after a while?

@bmtran (Bryant Tran) on 11 Feb 2012

actually, this is the first time i've used it without essentially copying Alfonso's code, so it's still new and fresh for me =P

Benjamin Kraus on 12 Feb 2012

Can someone explain to me how this function works (even if it is a trick)? I'm trying to parse through the code, but how it works isn't clear to me.

@bmtran (Bryant Tran) on 12 Feb 2012

the sparse function places the values (third input) into the row and column specified, 1st and second inputs respectively. if there are any overlapping coordinates then it sums them, so I created a matrix that, when fed into sparse, would sum the rows, sum the columns, and sum the diagonals in each direction. Then I Cody-fied it (teehee) by changing these indices into a string of characters, which Cody sizes as small, and subtracting a base character from it. does that make sense now?

@bmtran (Bryant Tran) on 12 Feb 2012

it might make more sense to look at one of my other solutions that uses the str2num function instead of the letter thing...

Test Suite

Test	Status	Code Input and Output
1	Pass	%% Eight Queens Solution Checker Test Suite
2	Pass	%% % Unique solution #6 from % http://en.wikipedia.org/wiki/Eight_queens_puzzle in1 = [ ... 0 0 0 0 1 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 1 0 0 0 0 0 0 0 0 0 0 1 0 1 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 1 0 0 0 0 0 0 ]; out1 = isEightQueensSolution(in1); assert(islogical(out1)); assert(isequal(out1, 1));
3	Pass	%% % Unique solution #7 in2 = [ ... 0 0 0 0 1 0 0 0 0 0 0 0 0 0 1 0 0 0 0 1 0 0 0 0 1 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 1 0 0 0 1 0 0 0 0 0 0 ]; out2 = isEightQueensSolution(in2); assert(isequal(out2, 1));
4	Pass	%% % Unique solution #10 in3 = [ ... 0 0 0 0 0 1 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 1 0 0 0 0 0 1 0 0 0 0 0 ]; out3 = isEightQueensSolution(in3); assert(isequal(out3, 1));
5	Pass	%% % Unique solution #11 in4 = [ ... 0 0 0 1 0 0 0 0 0 0 0 0 0 0 1 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 1 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 1 0 0 0 0 0 ]; out4 = isEightQueensSolution(in4); assert(isequal(out4, 1));
6	Pass	%% in5 = [ ... 0 0 0 0 1 0 0 0 0 0 1 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 1 0 1 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 1 0 0 0 0 0 0 ]; out5 = isEightQueensSolution(in5); assert(isequal(out5, 0));
7	Pass	%% in6 = [ ... 0 0 1 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 1 0 0 0 0 1 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 1 0 0 0 1 0 0 0 0 0 0 ]; out6 = isEightQueensSolution(in6); assert(isequal(out6, 0));
8	Pass	%% in7 = [ ... 0 0 0 0 0 1 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 1 0 0 1 0 0 0 0 0 0 0 0 0 1 0 0 0 ]; out7 = isEightQueensSolution(in7); assert(isequal(out7, 0));
9	Pass	%% in8 = [ ... 0 0 0 1 0 0 0 0 0 0 0 0 0 0 1 0 1 0 0 0 0 0 0 0 0 0 0 0 1 0 0 1 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 1 0 0 0 0 0 ]; out8 = isEightQueensSolution(in8); assert(isequal(out8, 0));
10	Pass	%% % Only 7 queens in9 = [ ... 0 0 0 0 1 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 1 0 0 0 0 0 0 ]; out9 = isEightQueensSolution(in9); assert(isequal(out9, 0));
11	Pass	%% % Row and column constraint satisfied but % not diagonal constraint. in10 = eye(8); out10 = isEightQueensSolution(in10); assert(isequal(out10, 0));

Problem 306. Eight Queens Solution Checker

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Problem 306. Eight Queens Solution Checker

Test Suite

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