Matlab本人文科生不太行

Question

产生一串个数为1000的0到1均匀分布的随机数。
用两种下标索引方式，将这串数中大于平均值的数找出来，并从大到小进行排序
整段程序计时。

Answer 1

第一种：

tic;
A=rand(10,100);
[r,c] = size(A);
B = [];
b=1;
average=mean(A(:));
for i =1:r
    for j = 1:c
        if A(i,j)>average
            B(b)=A(i,j);
            b=b+1;
        end
    end
end
B = sort(B,'descend');
toc;

第二种：

tic;
A=rand(10,100);
A=A(:);
L = size(A);
B = [];
b=1;
average=mean(A(:));
for i =1:L
    if A(i)>average
            B(b)=A(i);
            b=b+1;
    end
end
B = sort(B,'descend');
toc;