Most-Visited Exhibit

Find the exhibit with the highest total visitor count, breaking ties by fewest contributing visit records.

A museum logs visitor counts for its exhibits throughout the day. You are given a list of visit records, each naming the exhibit and how many visitors arrived at that time, in the order the visits happened. Add up the total visitor count for each exhibit. Return the exhibit with the highest total visitor count. If two or more exhibits are tied for the highest total, return whichever of those exhibits reached its total using the fewest separate visit records.