I have a mistake in loops

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sznailc 2021-11-5

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1580014-i-have-a-mistake-in-loops

编辑： Stephen23 2021-11-5

Hello, I have somewhere a mistake that if N = 1000 the output misses some lines (don't know which), so I suppose there's a mistake somewhere in for loops. It works correctly with N = 50, 100, 500.

function [R, I] = problem2B(N)
I = 0;
for a = 3:N
    for b = a:N
        for c = b:N
            if (a^2 + b^2) == c^2 && a+b+c < N
                R(I+1, :) = [a+b+c, a, b, c];
                I = I + 1;
            elseif N < 12
                R = zeros(4, 1);
            end
        end
    end
end
if N <= 50
    R = reshape(nonzeros(R), I, 4);
else
    R = sortrows(R, 1);
end
end

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sznailc 2021-11-5

编辑：sznailc 2021-11-5

I have a test file that says, that not all possible pythagorean triples are displayed with N = 1000. Therefore I think there has to be a mistake with indexes that it skips some possible triples.

Stephen23 2021-11-5

编辑：Stephen23 2021-11-5

在 MATLAB Online 中打开

Note that if you change to

R = zeros(0,4);

then you can get rid of NONZEROS and RESHAPE.

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采纳的回答

Steven Lord 2021-11-5

2
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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1580014-i-have-a-mistake-in-loops#answer_824809

Does your problem ask you to find all Pythagorean triples whose elements sum to less than 1000 or all whose elements sum to less than or equal to 1000?