## USACO 2017 January Contest. Problem 1. Cow Dance Show

After several months of rehearsal, the cows are just about ready to put on their annual dance performance; this year they are performing the famous bovine ballet “Cowpelia”. The only aspect of the show that remains to be determined is the size of the stage. A stage of size K can support K cows dancing simultaneously. The N cows in the […]

## 1477. Find Two Non-overlapping Sub-arrays Each With Target Sum

Given an array of integers arr and an integer target. You have to find two non-overlapping sub-arrays of arr each with sum equal target. There can be multiple answers so you have to find an answer where the sum of the lengths of the two sub-arrays is minimum. Return the minimum sum of the lengths of the two required sub-arrays, or return -1 if you cannot find such two […]

## Cut Ribbon

Given an array of integers with elements representing lengths of ribbons. Your goal is to obtain k ribbons of equal length cutting the ribbons into as many pieces as you want. Find the maximum integer length L to obtain at least k ribbons of length L. Example 1: First, we will find the largest length of ribbon, as we […]

## Leetcode – 23. Merge k Sorted Lists

You are given an array of k arrays/linked-lists arrays, each array/linked-list is sorted in ascending or descending order. Merge all the arrays/linked-lists into one sorted array/linked-list and return it. Example 1: Input: arrays= [[1,4,5],[1,3,4],[2,6]] Output: [1,1,2,3,4,4,5,6] Explanation: The arrays/linked-lists are: [ 1->4->5, 1->3->4, 2->6 ] merging them into one sorted array/list: 1->1->2->3->4->4->5->6 Constraints: k == arrays.length 0 <= […]

## Computer Networks

Computer Networks. Part One: LANs and WANs Computer Networks. Part Two: Network Hardware Computer Networks. Part Three: Ethernet Fundamentals Computer Networks. Part Four: LAN Topology Computer Networks. Part Five: Switched Ethernet LANs Computer Networks. Part Six: The TCP/IP Protocol Stack and Routers Domain Name System DNS

## Permutation and Combination

Permutation – position (order) matters. = N! / (N – r)!. Building words with {a,b,c} are also permutation problem with r = {1,2,3..N} Combination – position (order) doesn’t matter = N! / (N – r)! * r! . Combination is a part of Permutation set. All possible combination means, generating combination for r = {0,1.. […]