Tic Tac Toe Puzzle | Puzzles for Interview - Interview Preparation PDF Download

Introduction

In this puzzle, the game of Tic Tac Toe is being played between two intelligent players. After six moves, the board looks like this:

Method

After analyzing the game board, it can be concluded that O will win the game. This is because in order for X to win, the seventh mark must be placed in square 5, which is a win situation for both X and O. Therefore, the sixth mark must have been placed in a line already containing two of the opponent's marks. There were two possibilities for the sixth mark – O in square 7 or X in square 9.

Which Was the Sixth Mark and at Which Position?

Since we know that both players are intelligent, we can eliminate the possibility of O placing their mark in square 7 for the sixth move. Instead, O would have placed their mark in square 5, which guarantees a win. Therefore, the sixth mark must have been X in square 9.

Conclusion

Based on the analysis, it can be concluded that O will win the game and the sixth mark was X in square 9. By thinking ahead and strategizing, both players were able to make intelligent moves, leading to a successful outcome for one player.