Problem 18. Bullseye Matrix

Solution 593338

Submitted on 7 Mar 2015 by E. Cheynet

Size: 107
Leading solution size is 7.

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1 Comment

1 Comment

E. Cheynet on 7 Mar 2015

more elegant solution than a loop: Use the LDL decomposition on the bullseye matrix and you will find an interesting L and D matrix. THe D matrix is diagonale and can be built using n only. THe matrix L is the sum of a lower triangular matrix whose lowest part is put to zero using the mirrored triangular matrix. Finally the identity matrix is added :)

Test Suite

Test	Status	Code Input and Output
1	Pass	%% n = 5; a = [3 3 3 3 3; 3 2 2 2 3; 3 2 1 2 3; 3 2 2 2 3; 3 3 3 3 3]; assert(isequal(bullseye(n),a));
2	Pass	%% n = 7; a = [4 4 4 4 4 4 4; 4 3 3 3 3 3 4; 4 3 2 2 2 3 4; 4 3 2 1 2 3 4; 4 3 2 2 2 3 4; 4 3 3 3 3 3 4; 4 4 4 4 4 4 4]; assert(isequal(bullseye(n),a))

Test

Status

Code Input and Output

Pass

%% n = 5; a = [3 3 3 3 3; 3 2 2 2 3; 3 2 1 2 3; 3 2 2 2 3; 3 3 3 3 3]; assert(isequal(bullseye(n),a));

Pass

%% n = 7; a = [4 4 4 4 4 4 4; 4 3 3 3 3 3 4; 4 3 2 2 2 3 4; 4 3 2 1 2 3 4; 4 3 2 2 2 3 4; 4 3 3 3 3 3 4; 4 4 4 4 4 4 4]; assert(isequal(bullseye(n),a))

Problem 18. Bullseye Matrix

Test Suite

Suggested Problems

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Problem 18. Bullseye Matrix

Test Suite

Suggested Problems

More from this Author95

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