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Given an integer, convert it to a roman numeral.Input is guaranteed to be within the range from 1 to 3999.Solution: 1 public class Solution { 2 pu... 阅读全文
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Write a function to find the longest common prefix string amongst an array of strings.Solution:第0个字符串和其他字符串逐个求前缀对strs做了一个排序操作：Arrays.sort(strs);使得最终结果... 阅读全文
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Given a non-negative number represented as an array of digits, plus one to the number.The digits are stored such that the most significant digit is at... 阅读全文
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Determine whether an integer is a palindrome. Do this without extra space.click to show spoilers.Some hints:Could negative integers be palindromes? (i... 阅读全文
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Given a binary tree, check whether it is a mirror of itself (ie, symmetric around its center).For example, this binary tree is symmetric: 1 / \ ... 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 binary tree, determine if it is height-balanced.For this problem, a height-balanced binary tree is defined as a binary tree in which the depth... 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 a binary tree struct TreeLinkNode { TreeLinkNode *left; TreeLinkNode *right; TreeLinkNode *next; }Populate each next pointe... 阅读全文
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Givennnon-negative integers representing an elevation map where the width of each bar is 1, compute how much water it is able to trap after raining.Fo... 阅读全文