Problem 23. Finding Perfect Squares
Solution Stats
Problem Comments

37 Comments
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 forloops, 1 function, 1 ifcondition.
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
@Tran Up to floating point arithmetic, sqrt(a(i))^2 is the same as a(i), so you're really just testing whether the vector a is nonempty.
(Note that the failing cases are the one where the correct answer is "false", while the ones where you succeed are the ones where it is "true").
Solution Comments
Show commentsProblem Recent Solvers16539
Suggested Problems

2050 Solvers

429 Solvers

First nonzero element in each column
819 Solvers

Convert a Cell Array into an Array
1374 Solvers

623 Solvers
More from this Author96
Problem Tags
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!