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Invert a binary tree. Example 1 1 / \ / \ 2 3 => 3 2 / \ 4 4 Challenge Do it in recursion is acceptable, can you do it without recursion? 1. 递归 /** * 阅读全文
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Sort a linked list using insertion sort. Example Given 1->3->2->0->null, return 0->1->2->3->null. 思路也比较直接，insertion sort，要注意的就是操作linkedlist的一些问题 /** * 阅读全文
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Given a binary search tree and a new tree node, insert the node into the tree. You should keep the tree still be a valid binary search tree. Example G 阅读全文
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Given a non-overlapping interval list which is sorted by start point. Insert a new interval into it, make sure the list is still in order and non-over 阅读全文
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Check if two binary trees are identical. Identical means the two binary trees have the same structure and every identical position has the same value. 阅读全文
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In data structure Hash, hash function is used to convert a string(or any other type) into an integer smaller than hash size and bigger or equal to zer 阅读全文
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Write an algorithm to determine if a number is happy. A happy number is a number defined by the following process: Starting with any positive integer, 阅读全文
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Determine the number of bits required to flip if you want to convert integer n to integer m. Example Given n = 31 (11111), m = 14 (01110), return 2. N 阅读全文
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Flatten a binary tree to a fake "linked list" in pre-order traversal. Here we use the right pointer in TreeNode as the nextpointer in ListNode. Exampl 阅读全文
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For a given sorted array (ascending order) and atarget number, find the first index of this number inO(log n) time complexity. If the target number do 阅读全文