You and a friend have received a special gold chain as a gift. The chain links each have an integer weight, not necessarily the same.
You and your friend must choose one of the links to be removed and provided to charity, after which the chain will be reconnected. After that, you can choose one place along the chain to split it into two, such that it creates two equally weighted sections for you and your friend to take home.
Given an input chain (a list of link weights), determine if a solution is possible.
This problem asks whether, after removing one link and reconnecting the chain, the remaining chain can be split into two sections with equal total weight. A common approach is to use prefix sums to reason about section weights efficiently, then test whether there exists a removable link and a cut position that makes the two sides balance. The key is to turn the chain operations into interval-sum checks rather than simulating the process directly.
