## Solution to Hills

7 Sep

Question Name: Hills Question Description: An integer array store the heights of some consecutive hills. Find a minimum integer N, so that you could increase/decrease the heights of the hills by any integer in range [0, N]. After the adjustment, … Read More »

## Solution to Deviation

4 Sep

Question Name: Deviation Question Description: Given an array of integer elements and an integer d, please consider all the sequences of d consecutive elements in the array. For each sequence we compute the difference between the maximum and the minimum … Read More »

## Solution to Find the Abnormal Number

29 Aug

This morning, I suddenly remembered this challenge. But I nearly forgot the answer. I’d better to record it here for latter review. Question Name: Find the Abnormal Number Question Description: in a given integer array, every number, except one, appears … Read More »

## Solution to Simulate Stack With Two Queues

2 Aug

Question Name: Simulate Stack With Two Queues

## Solution to Count Visible Nodes in Binary Tree

25 Jul

Questioin Name: Count Visible Nodes in Binary Tree Question: In a binary tree, if in the path from root to the node A, there is no node with greater value than A’s, this node A is visible. We need to … Read More »

## Solution to Print Tree By Columns

25 Jul

Question Name: Print Tree By Columns Question: print tree by columns, from leftmost column to rightmost column. For each node in i(th) column, if son(s) exist, its left son is in the (i-1)th column, and right son in the (i+1)th … Read More »

## Generate a subset in a uniformly random manner

21 Feb

Question: To generate a K-subset in a uniformly random manner from N elements. We have two slightly different solutions. The first one is quite straightforward:  shuffle the elements, and then return the first K elements. In such solution, the space … Read More »

## Find a Duplicate Item In an Array of Shuffled Consecutive Integers

16 Mar

Question: if you hava an array with n integers. These integers are in random order. And each interger is between 1 and n-1, including 1 and n-1. Additionally, there is one and only one integer, which appears twice, while all … Read More »