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An abbreviation of a word follows the form . Below are some examples of word abbreviations: a) it --> it (no abbreviation) 1 b) d|o|g --> d1g 1 1 1 1 阅读全文
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Given an interval list which are flying and landing time of the flight. How many airplanes are on the sky at most? If landing and flying happens at th 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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The API: int read4(char *buf) reads 4 characters at a time from a file. The return value is the actual number of characters read. For example, it retu 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. You can a 阅读全文
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Given a binary tree, determine if it is a valid binary search tree (BST). Assume a BST is defined as follows: The left subtree of a node contains only 阅读全文
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Given a collection of intervals, merge all overlapping intervals. Given a collection of intervals, merge all overlapping intervals. Given a collection 阅读全文
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Given a string containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid. Given a string containing just 阅读全文
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Given a string, find the first non-repeating character in it and return it's index. If it doesn't exist, return -1. Given a string, find the first non 阅读全文
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Given an integer, convert it to a roman numeral. The number is guaranteed to be within the range from 1 to 3999. Given an integer, convert it to a rom 阅读全文