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题目： Design a stack that supports push, pop, top, and retrieving the minimum element in constant time. push(x) -- Push element x onto stack. pop() -- R 阅读全文
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1. 魔法币 DESCRIPTION 小易准备去魔法王国采购魔法神器,购买魔法神器需要使用魔法币,但是小易现在一枚魔法币都没有,但是小易有两台魔法机器可以通过投入x(x可以为0)个魔法币产生更多的魔法币。魔法机器1:如果投入x个魔法币,魔法机器会将其变为2x+1个魔法币魔法机器2:如果投入x个魔法币 阅读全文
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题目： Given a non-negative integer represented as a non-empty array of digits, plus one to the integer. You may assume the integer do not contain any le 阅读全文
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题目： You are given an n x n 2D matrix representing an image. Rotate the image by 90 degrees (clockwise). Note:You have to rotate the image in-place, wh 阅读全文
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题目： Determine if a Sudoku is valid, according to: Sudoku Puzzles - The Rules. The Sudoku board could be partially filled, where empty cells are filled 阅读全文
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题目： The set [1,2,3,…,n] contains a total of n! unique permutations. By listing and labeling all of the permutations in order,We get the following sequ 阅读全文
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题目： Given an array of integers, return indices of the two numbers such that they add up to a specific target. You may assume that each input would hav 阅读全文
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题目： Given an unsorted array of integers, find the length of the longest consecutive elements sequence. For example,Given [100, 4, 200, 1, 3, 2],The lo 阅读全文
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题目： Follow up for "Search in Rotated Sorted Array":What if duplicates are allowed? Would this affect the run-time complexity? How and why? Suppose an 阅读全文
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题目： Suppose an array sorted in ascending order is rotated at some pivot unknown to you beforehand. (i.e., 0 1 2 4 5 6 7 might become 4 5 6 7 0 1 2). Y 阅读全文