check if a vector equals to a row in a 2D matrix

[benllera]

I have a class template for a 2dimensional matrix (nested std::vector in std::vector) and I need a function that takes a std::vector as argument and checks if it is equal to any row of the matrix.

[redhead]

How about a loop through your matrix, checking every 2.nd dimension item up against your comparison 2.nd dimesnion item.
Using the bool operator== (const container& c1, const container& c2);, it is described as:

 Performing a comparison one vector to another takes linear time.
Two `containers` are equal if:

   1. Their size is the same, and
   2. Each member in location i in one vector is equal to the
       member in location i in the other vector.

Comparisons among vectors are done lexicographically.

As described in the C++ reference
It will require a nested loop, but you could do a quick check uppon starting the outer loop, to make sure the item run through the inner loop will allways contain the least items, keeping that as fast as possible.

[benllera]

Thank you.