It’s not hard to see that this will end up sorting all the amounts in increasing order. So you only have to sort the input. Make sure you know how to use the default sorting methods from your favorite language: here is a helpful link.
There is a dent if the position of two consecutive cars is overlapping. So to solve this it might help to put cars in order and then check if any pair of consecutive cars overlaps.
We can only remove elements that are consecutive. So it might help to put all elements in order and then check if we can remove them from smallest to largest.
Note that after doing any number of operations, all the indices containing odd numbers still contain odd numbers and all indices containing even numbers also contain even numbers. This observation should tell you something about whether you can do it or not (look at the sorted array and see if it satisfies it).
This is more challenging than the previous ones, so we won’t give any major hints. The one observation that might help is that because you have to double the number of problems in each contest, you can only have at most log(10^9) contests, which is a small number.
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