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You are given a tree (an undirected acyclic connected graph) with N nodes, and edges numbered 1, 2, 3...N-1. Each edge has an integer value assigned t 阅读全文
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There are N (1 ≤ N ≤ 105) cities on land, and there are N - 1 wires connecting the cities. Therefore, each city can transmit electricity to all other 阅读全文
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题目描述 这次小可可想解决的难题和中国象棋有关，在一个N行M列的棋盘上，让你放若干个炮（可以是0个），使得没有一个炮可以攻击到另一个炮，请问有多少种放置方法。大家肯定很清楚，在中国象棋中炮的行走方式是：一个炮攻击到另一个炮，当且仅当它们在同一行或同一列中，且它们之间恰好 有一个棋子。你也来和小可可一 阅读全文
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打印严格上升子序列； 阅读全文
摘要：
You are given a tree (an acyclic undirected connected graph) with N nodes, and edges numbered 1, 2, 3...N-1. We will ask you to perfrom some instructi 阅读全文