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Remove Palindromic Subsequences (E) 题目 Given a string s consisting only of letters 'a' and 'b'. In a single step you can remove one palindromic subseq 阅读全文
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Design HashMap (E) 题目 Design a HashMap without using any built-in hash table libraries. To be specific, your design should include these functions: pu 阅读全文
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Short Encoding of Words (M) 题目 A valid encoding of an array of words is any reference string s and array of indices indices such that: words.length == 阅读全文
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Average of Levels in Binary Tree (E) 题目 Given a non-empty binary tree, return the average value of the nodes on each level in the form of an array. Ex 阅读全文
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Intersection of Two Linked Lists (E) 题目 Write a program to find the node at which the intersection of two singly linked lists begins. For example, the 阅读全文
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Set Mismatch (E) 题目 You have a set of integers s, which originally contains all the numbers from 1 to n. Unfortunately, due to some error, one of the 阅读全文
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Distribute Candies (E) 题目 Alice has n candies, where the ith candy is of type candyType[i]. Alice noticed that she started to gain weight, so she visi 阅读全文
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Maximum Frequency Stack (H) 题目 Implement FreqStack, a class which simulates the operation of a stack-like data structure. FreqStack has two functions: 阅读全文
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Validate Stack Sequences (M) 题目 Given two sequences pushed and popped with distinct values, return true if and only if this could have been the result 阅读全文
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Shortest Unsorted Continuous Subarray (M) 题目 Given an integer array nums, you need to find one continuous subarray that if you only sort this subarray 阅读全文