Matched with my ex on tinder.. what do I do?

I haven't used tinder in months (I'm in college so no need) but recently I downloaded it because I was bored at my
internship. I always just swipe right to everyone because I use it out of boredom and don't really care who I match with. Turns out on one of my swiping binges I swiped right on my ex because a few days after using tinder I got the notification that we matched. We dated for three years in high school and haven't talked much at all since college started (we're going to be juniors). We had a nasty breakup but have been formal with each other in the past few months (just nice to each other if we saw the other in person). About a day before we matched, her friend who I never talked to or hungout with when we dated asked to meet her at the bars with me and my friends (we never hangout with her or her friends anymore) so I'm a little suspicious. I don't really want anything from my ex unless it's just friendly. What should I do?
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Update: when I say I swipe right for everyone I just swipe right as fast as I can without looking at who it is lol. The life of an intern
Matched with my ex on tinder.. what do I do?
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