Counting occurences of each number in a column when it's equal to all numbers in the same line?

I have, for example, the following matrix P:

1 2 3
2 2 2
3 3 3
4 4 1
4 4 4
2 2 2
1 4 2

How can I count the occurences of each number in the first column, only when it's equal to all numbers in the same line? For this example, the result would be:

0
2
1
1

I've tried something like this:

alpha = unique(P);
O = zeros(size(alpha));

for k = 1 : length(alpha)
    O(k) = sum(P(:,1) == alpha(k));
end

which counts the occurences for the first column of P, but I don't know how to exclude the cases where the line isn't all the same number. How should I alter my code?

Answer 1

[KALYAN ACHARJYA]

P=[1 2 3
2 2 2
3 3 3
4 4 1
4 4 4
2 2 2
1 4 2];
[r c]=size(P);
for i=1:r
    if range(P(i,:))==0
    data=ismember(P,P(i,:),'rows');
    result(i)=sum(data);
    else
    result(i)=0;
    end
end
result'

Result:

ans =
     0
     2
     1
     0
     1
     2
     0

Answer 2

[Image Analyst]

Try this:

P=[1 2 3
2 2 2
3 3 3
4 4 1
4 4 4
2 2 2
1 4 2];
allTheSame = P(:, 1) == P(:, 2) & P(:, 1) == P(:, 3) % Rows where all 3 values are the same.
counts = histcounts(P(allTheSame, 1), 1:max(P)+1)

You'll see

allTheSame =

7×1 logical array

0

1

1

0

1

1

0

counts =

0 2 1 1