摘要：
Design a data structure that supports all following operations in average O(1) time. Example: 阅读全文
摘要：
Shuffle a set of numbers without duplicates. Example: 阅读全文
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Implement a trie with insert, search, and startsWith methods. Note:You may assume that all inputs are consist of lowercase letters a-z. 阅读全文
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Given an integer array nums, find the sum of the elements between indices i and j (i ≤ j), inclusive. The update(i, val) function modifies nums by upd 阅读全文