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Design a stack that supports push, pop, top, and retrieving the minimum element in constant time.push(x) -- Push element x onto stack.pop() -- Removes... 阅读全文
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Given two sorted integer arrays A and B, merge B into A as one sorted array.Note:You may assume that A has enough space (size that is greater or equal... 阅读全文
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The string"PAYPALISHIRING"is written in a zigzag pattern on a given number of rows like this: (you may want to display this pattern in a fixed font fo... 阅读全文
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Given a string, determine if it is a palindrome, considering only alphanumeric characters and ignoring cases.For example,"A man, a plan, a canal: Pana... 阅读全文
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Reverse digits of an integer.Example1:x = 123, return 321Example2:x = -123, return -321Have you thought about this?Here are some good questions to ask... 阅读全文
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Determine whether an integer is a palindrome. Do this without extra space.判断一个整数是不是回文整数（例12321）。不能使用多余的空间。Some hints:Could negative integers be palind... 阅读全文
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Given a stringsconsists of upper/lower-case alphabets and empty space characters' ', return the length of last word in the string.If the last word doe... 阅读全文
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Given a linked list, remove thenthnode from the end of list and return its head.For example, Given linked list: 1->2->3->4->5, and n = 2. After re... 阅读全文
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Given an array and a value, remove all instances of that value in place and return the new length.The order of elements can be changed. It doesn't mat... 阅读全文
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Given two binary strings, return their sum (also a binary string).For example,a ="11"b ="1"Return"100".解题思路：从两个子字符尾部遍历字符；每次得到新的字符插入结果字符串的头部；解题步骤：1、建立返... 阅读全文