Pairing up Socks

On a nice day, Babai, a computer scientist, received back all 6 pairs of my blue\color{blue}{blue} and red\color{red}{red} socks in a laundry basket. He needed to pair them up into pairs of same color for me.

Being a computer scientist, he wondered what would be a good way to sort them out. Can you help him by figuring out the faster way to sort these?

Swap and Go:

  1. Lay the socks on the table side by side.
  2. While there are some blue\color{blue}{blue} socks in the last 6 socks, do the following:
    • Going from left to right, if there is a red\color{red}{red} sock to the right of a blue\color{blue}{blue} sock, exchange them.
  3. Now, all 6 pairs of adjacent socks are each of the same color. So, take two at a time and pair them up.

Throw into Buckets:

  1. Lay the socks on the table side by side. Take two buckets, red\color{red}{red} and blue\color{blue}{blue}.
  2. For all the socks on the table, check which of them are red\color{red}{red}, one by one:
    • if a sock is red\color{red}{red}, put it in the red\color{red}{red} bucket;
    • if a sock is blue\color{blue}{blue}, put it in the blue\color{blue}{blue} bucket.
  3. Now, we know that all the red\color{red}{red} and blue\color{blue}{blue} socks are each in the bucket of the same color. Taking two of them at a time from the same bucket, pair them up.

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