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The A&B&C three problems are not hard at all, but it still takes me 47 minutes to solve them.↵
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The D&E&F three problems are really hard to solve.↵
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It seems that from ranking 50 to ranking 900 are all contestants who solves three problems, it just depends on how fast they do it.↵
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There are also past ARC's that contains easy A&B&C, but extremely hard D&E&F which, for me, are impossible to do.
