Can two groups of N people find each other around a circle?
<p>This is an algorithmic problem and I'm not sure it has a solution. I think it's a specific case of a more generic computer science problem that has no solution but I'd rather not disclose which one to avoid planting biases. It came up from a real life situation in which mobile phones were out of credit and thus, we didn't have long range communications.</p>

<p>Two groups of people, each with 2 people (but it might be true for N people) arranged to meet at the center of a park but at the time of meeting, the park is closed. Now, they'll have to meet somewhere else around the park. Is there an algorithm each and every single individual could follow to converge all in one point?</p>

<p>For example, if each group splits in two and goes around and when they find another person keep on going with that person, they would all converge on the other side of the park. But if the other group does the same, then, they wouldn't be able to take the found members of the other group with them. This is not a possible solution.</p>

<p>I'm not sure if I explained well enough. I can try to draw a diagram.</p>