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When I did interviews for Google, one of my go-to interview questions was to ask the candidate to determine if someone had won a game of tic-tac-toe. The candidate could choose the board representation and the language to use; I just wanted to see them write the code that checked for a winner. Inevitably, the candidate would choose a 2D array to represent the board. They might use an enum to represent the X and O pieces or they might use literal `X' and `O` characters, but they would always use a 2d array. Then they'd write the code to check for a winner. Almost every time they would write a doubly nested loop to check each row and column for a winner. This has a hidden trap. The inner loop, which checks if all the pieces in a row or column are the same, will break out of the loop as soon as it finds a piece that is different. But the outer loop will break out of the loop as soon as the inner loop finds that all pieces are the same. This difference in the break conditions of the inner…