Matlab_ExerciseSheet3

function x = SHEET3TASK2(x)
n = numel(x);
if n == 1
    return
end
min_ind = finde_min(x,n);
if min_ind > 1
    x = tausche(x,1,min_ind);
end
x(2:n) = SHEET3TASK2(x(2:n));
end

function ind = finde_min(x,n)
ind = 1;
ind_value = x(1);
for k=2:n
    if x(k) < ind_value
        ind = k;
        ind_value = x(k);
    end
end
end

function x = tausche(x,ind1,ind2)
merke_x_ind1 = x(ind1);
x(ind1) = x(ind2);
x(ind2) = merke_x_ind1;
end

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function [x,indices] = SHEET3TASK2b(x)
n = numel(x);
indices = 1:n;
if n==1
    return
end
for k=1:n-1
    min_ind = finde_min(x(k:n),n-k+1);
    %disp(["k=",k, ": ", "min_ind=",min_ind])
    if min_ind > 1
        x = tausche(x,k,min_ind+k-1);
        indices = tausche(indices,k,min_ind+k-1);
    end
end
end

function ind = finde_min(x,n)
ind = 1;
ind_value = x(1);
for k=2:n
    if x(k) < ind_value
        ind = k;
        ind_value = x(k);
    end
end
end

function x = tausche(x,ind1,ind2)
merke_x_ind1 = x(ind1);
x(ind1) = x(ind2);
x(ind2) = merke_x_ind1;
end

-----------

function x_sorted = SHEET3TASK3(x)
n = numel(x);
if n<=1
    return
end
mitte = floor(n/2);
links = x(1:mitte);
links = SHEET3TASK3(links);
rechts = x(mitte+1:n);
rechts = SHEET3TASK3(rechts);
x_sorted = verschmelze(links,rechts);
end

function x = verschmelze(links,rechts)
n_links = numel(links);
n_rechts = numel(rechts);
x = zeros(1,n_links+n_rechts);
k = 1;
while n_links ~= 0 && n_rechts ~= 0
    if rechts(1) < links(1)
        x(k) = rechts(1);
        rechts = rechts(2:end);
        n_rechts = n_rechts-1;
    else
        x(k) = links(1);
        links = links(2:end);
        n_links = n_links-1;
    end
    k = k+1;
end
if n_links == 0 && n_rechts == 1
    x(end-n_rechts+1) = rechts(1:n_rechts);
end
if n_rechts == 0 && n_links == 1
    x(end-n_links+1) = links(1:n_links);
end
end