Problem 90. Connect Four Win Checker

Connect Four is a game where you try to get four pieces in a row. For this problem, you are given a grid of numbers that represents a game between Mr. One and Mr. Two. Your job is to return 1 if Mr. One wins, 2 if Mr. Two wins, and 0 if there is no winner yet. There will never be a two-winner state.

Note that this is a generalized game of Connect Four in which the board might vary in dimension (it is guaranteed to be 4 or greater in each dimension). Also in Connect Four the pieces fall to the bottom of the grid, but in this problem the pieces can appear in any position.

Example

In the board below, the pieces are 1s and 2s. Empty spots are zeros. Mr. Two wins because the third column has four consecutive twos. So the output of your function should be 2.

b = [0 1 1 0 2;
     0 1 2 2 1;
     1 0 2 2 2;
     1 1 2 2 1;
     1 1 2 1 0];