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问题描述 On the way home, Karen decided to stop by the supermarket to buy some groceries. She needs to buy a lot of goods, but since she is a student her 阅读全文
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问题描述 You are given a weighed undirected connected graph, consisting of n vertices and m edges. You should answer q queries, the i th query is to find 阅读全文
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问题描述 You are given an unweighted tree with n vertices. Then n 1 following operations are applied to the tree. A single operation consists of the follo 阅读全文
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问题描述 The competitors of Bubble Cup X gathered after the competition and discussed what is the best way to get to know the host country and its cities. 阅读全文