The classic board game "connect 4" in Haskell.
Inspired by the coursework of AFP class.
Human vs Computer using minmax game tree.
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| O | O | | | | | |
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| X | X | | | | | |
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| X | O | | X | X | | |
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| O | X | O | O | O | | |
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| X | X | X | O | O | O | |
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| X | X | O | O | O | X | |
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1 2 3 4 5 6 7
You win!