Problem 23. Finding Perfect Squares

Another of the classic "check if MATLAB has a function that does this already" problems...

What about a vector like [2 3 1]? The top solution will still return true because 1^2 is still one but it is not the square of one of the OTHER numbers.

is the Str2func construct really more effective???
Is it possible that this distorts the metric a bit?

It is currently impossible to submit a solution for this problem. The web page will never load.

The problem description states that one of the numbers has to be a square of one of the OTHER numbers. Still, the test suite tests if [1] gives true. I think [1] should give false, or that describtion be modified.

Agree with Mattias. the length of input vector should be 2 or larger.

The difference between test 4 and 5 which returns different answers is the number 36.. but 36 is not a square root of any number of the list in test 4!!

Agree with Mattias: the Test Suite is defective, and not consistent with the problem specification.
Having an input of [1] is OK, but result should be false, as there is no OTHER element to compare the 1 to!

easy

Fun question!

the word "other" should be ignored in the description...

fun

Good question!

Clever problem

good

The heading reads:
"...a square of one of the OTHER numbers...".

How can the function be expected to return [true] for a = [1]?
It makes no sense.

Good question

This problem is very good

intersect的返回值为一个向量，即使a和b的交集为空集，返回值仍为向量
x=[20:30]
例如：intersect(x.^2,x)

ans =

空的 1×0 double 行向量
所以isvector(intersect(x.^2,x))是错误的
而isempty是判断数组是不是空的，所以isempty可行

Tough one, but interesting

I solved it with 2 for-loops, 1 function, 1 if-condition.
It works, but there are more efficient ways apparently

Hey,the demand of this problem declare that "if one " and "the other",so if the intersect of x and x.^2 only have one value of 0 or 1,it may be return false because their squares are themselves, which is not satisfy the condition implied that c and c^2 is not one.

Nice Problem

The question asks if one number is the square of one of the OTHER numbers. Test 3 should return false.

Great problem

Nice

error in test 7 ! You missed 'd' in function.
fix it!!!!

Error has been fixed.

Good problem

Good beginners' question!

So far it is the most time consuming problem for me.

function b = issqr(a);
x = a.^2;
issqr = x;
c = ismember(a,x);
if any(c) == 1
'true'
else
'false'
end
end

Not sure why this isnt working any help would be appreciated

@Max Weinburg, you have to output logical values not string/char

Great problem for introducing to MATLAB

@Max Weinberg you can't use else because test1 will report an error

function b = isItSquared(a)
b = false;
for i = 1:length(a)
if any(a == sqrt(a(i))^2)
b = true;
return;
end
end
end
can sbd tell me why this code wrong at case 3, 7and 8