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理解 我们可以把N个数两两建立无向边（即任意两个结点之间都有边，也就是一个N个结点的完全图），然后对每个点作为起点，分别做一次深度优先遍历，当所有点都已经标记时输出当前的遍历路径，就是其中一个排列，这里需要注意，回溯的时候需要将原先标记的点的标记取消，否则只能输出一个排列。如果要按照字典序，则需要在 阅读全文
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1.题目A family hierarchy is usually presented by a pedigree tree where all the nodes on the same level belon... 阅读全文
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1.题目The string APPAPT contains two PAT's as substrings. The first one is formed by the 2nd, the 4th, and t... 阅读全文
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1.题目Eva would like to make a string of beads with her favorite colors so she went to a small shop to buy s... 阅读全文
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1.题目A Binary Search Tree (BST) is recursively defined as a binary tree which has the following properties:... 阅读全文
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1.题目According to Wikipedia:Insertion sort iterates, consuming one input element each repetition, and growi... 阅读全文