Step-BY-Step

摘要： Given a set of candidate numbers (C) and a target number (T), find all unique combinations inCwhere the candidate numbers sums toT.Thesamerepeated num... 阅读全文

摘要： Given an unsorted integer array, find the first missing positive integer.For example,Given[1,2,0]return3,and[3,4,-1,1]return2.Your algorithm should ru... 阅读全文

摘要： 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.For example,Given[0,1,0,2,1,0,1,3,2,1,2,1], return6.The above elevation map is represented by array [0,1,0,2,1,0,1,3,2,1,2,1]. In this case, 6 units of 阅读全文

摘要： Given a collection of numbers, return all possible permutations.For example,[1,2,3]have the following permutations:[1,2,3],[1,3,2],[2,1,3],[2,3,1],[3,... 阅读全文

摘要： Given an array of integers, every element appearsthreetimes except for one. Find that single one.Note:Your algorithm should have a linear runtime complexity. Could you implement it without using extra memory?创建一个长度为32的数组a，a[i]表示所有数字在i位出现的次数。假如a[i]是3的整数倍，则忽略；否则就把该位取出来组成答案。空间复杂度O(1).int sol1(int A[], 阅读全文

摘要： Given an array of integers, every element appearstwiceexcept for one. Find that single one.Note:Your algorithm should have a linear runtime complexity. Could you implement it without using extra memory?这题是Amazon的经典面试题。 最简单的解法是用hashmap，O(n)即可。但是要用额外的存储空间。或者是维持一个数组，用于存放没有被配对的数。用二分来更新这个数组，如果数组中没有当前数就加入 阅读全文

摘要： Question: There is a doubly linked list with next pointer and random pointer (points to an arbitrary node in list). You have to make a copy of the linked list and return. In the end original list shouldn't be modified. Time complexity should be O(n).这个是微软经典list题目之一: 铁索连舟. 本来是想自己写一篇总结的, 但是网上那篇英文的 阅读全文