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问题描述 给定一张 n个点,m条边的无向图。这张图的每个点有两个权值 ai , bi 。你将会从这张图中选出一个点作为起点,随后开始遍历这张图。你能到达一个节点 i当且仅当你的手上有至少 ai 元钱。当你到达一个节点 i后,你可以选择对这个点捐赠 bi 元。你需要对每个点捐赠一次。问你身上至少要带多 阅读全文
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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
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问题描述 给定一颗 n 个点的树,树边带权,试求一个排列 P ,使下式的值最大 $$ \sum_{i=1}^{n 1}maxflow(P_i,P_{i+1}) $$ 其中 maxflow ( s, t ) 表示从点 s 到点 t 之间的最大流,即从 s 到 t 的路径上最小的边权。 输入格式 第一行 阅读全文