# My code is short, but...is it the best efficient?

• ``````bool searchMatrix(vector<vector<int> > &matrix, int target)
{
vector<int> v;
for (int i = 0; i < matrix.size(); ++i)
for (int j = 0; j < matrix[i].size(); ++j)
v.push_back(matrix[i][j]);

return binary_search(v.begin(), v.end(), target);
}
``````

I think this proble has a better solution, but this code is so pretty....

• Could you solve this problem without extra space ?

• What do you think about the time complexity of this solution? And, do you really think it is fine to use `binary_search` in a real interview?

• O(n*m) . Sure, you can use std:binary_search and std:upper_bound in the interview, and if the interviewer ask you implement those functions , implement it. It is still better than write 20-30 lines code in a big function, in my opinion.

• No, this is worse than a linear search, since you have to go through every element.
You can do it faster by implementing binary search directly on the matrix.

• while you traversal you can get the answer, but it's not a good solution.
for (int i = 0; i < matrix.size(); ++i)
for (int j = 0; j < matrix[i].size(); ++j)
if (matrix[i][j] == target) return true;
return false;

• As you are already go through every entry of matrix why are you even bother to push it into some other array simply check if that element is present or not.

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