HACKER RANK: Common Child

Problem Link: https://www.hackerrank.com/challenges/common-child

Summary:
Given 2 strings of equal length what's the longest string that can be constructed such that it is a child of both.

For example:

Sample Input 1:
HARRY
SALLY

Sample Output 1:
2

Longest possible string is "AY"

Sample Input 2:
ABCDEF
FBDAMN

Sample Output 2:
2

Longest possible string is "BD"

Topic:
Dynamic Programming Approach: https://en.wikipedia.org/wiki/Dynamic_programming
Longest String Subsequence: https://en.wikipedia.org/wiki/Longest_common_substring_problem
                                                http://www.geeksforgeeks.org/longest-common-substring/

My Logic:

Let string str1 = HARRY and str2 = SALLY
So this is how i solved this question using DP(Dynamic Programming).

To view My Solution:
https://github.com/shivam04/hackerrank/blob/master/common-child.java

HACKER RANK: Sherlock and Anagrams

Problem Link: https://www.hackerrank.com/challenges/sherlock-and-anagrams

Given a string S, find the number of "unordered anagrammatic pairs" of substrings.

Input Format

First line contains T, the number of testcases. Each testcase consists of string S in one line.

Constraints 
1≤T≤10 
2≤length(S)≤100 
String S contains only the lowercase letters of the English alphabet.

Output Format

For each testcase, print the required answer in one line.

Logic:

Let's say S[i,j] denotes the substring Si,Si+1,⋯,Sj.

Match Subset Si  With Si+1, ....... Sj For anagram.

To View My Solution:

https://github.com/shivam04/hackerrank/blob/master/sherlock-and-anagrams.java

HACKER RANK: The Grid Search

Problem Link: https://www.hackerrank.com/challenges/the-grid-search

Summary:
Given a 2D array of digits, try to find the occurrence of a given 2D pattern of digits.

1234567890  
0987654321  
1111111111  
1111111111  
2222222222  

Assume we need to look for the following 2D pattern:

876543  
111111  
111111

If we scan through the original array, we observe that the 2D pattern begins at the second row and the third column of the larger grid (the 8 in the second row and third column of the larger grid is the top-left corner of the pattern we are searching for).

So, a 2D pattern of P digits is said to be present in a larger grid G, if the latter contains a contiguous, rectangular 2D grid of digits matching with the pattern P, similar to the example shown above.

Logic:

Match element by element for small array in large array.

To View My Solution:

https://github.com/shivam04/hackerrank/blob/master/the-grid-search.cpp