All Questions
15 questions
10votes
1answer
2kviews
Arranging 8 queens on an 8x8 board
Print all the ways of arranging eight queens on an 8x8 board. Rules: Queens should not share the same row, column, of any diagonal. Any comment on my solution? I didn't write unit tests but I ...
- 743
10votes
2answers
449views
You need to diversify your strings
Challenge: Write a program which prints all the permutations of a string in alphabetical order. Specifications: Your program should accept a file as its first argument. The file contains input ...
- 9,839
10votes
1answer
4kviews
Project Euler #14 -- longest Collatz sequence
I was reading this question and realized that I didn't know Python well enough to critique the algorithm. So I wrote a Java solution instead, which is inappropriate for that question. Since there's ...
- 6,974
9votes
4answers
3kviews
"What is the maximum that Player 1 can win?"
This is a question that I encountered in one of the competitive coding tests. The question goes as follows: A 2-player game is being played. There is a single pile of stones. Every stone has an ...
7votes
1answer
526views
An Army of Ones
I've been practicing using recursion lately and thought this was a case where it would prove really useful, is this good use or is there some superior non-recursive way to go about it? Challenge: ...
- 9,839
5votes
4answers
5kviews
Digital root recursive function
Haven't any experience writing recursive functions.(Generally tend to avoid them - not sure if that's a negative). What do you think about the following? This is also my first time using JUnit, I'd ...
- 9,839
5votes
3answers
959views
LeetCode 678: Valid Parenthesis String, Recursion memoization to DP
How can the following recursion + memoization code be converted into a tabulation format dynamic programming solution? The code is working, but I want to improve it. The challenge I am facing is ...
5votes
3answers
5kviews
Using recursion to count substrings (with exceptions to the rule) in Java
I am going through the CodingBat exercises for Java. Here is the one I have just finished: Given a string, compute recursively the number of times lowercase hi ...
- 1,302
5votes
1answer
2kviews
Finding if there is a subset that sums to a target value from an array of integers
I came across this problem. Problem Statement: Given an array of ints, is it possible to choose a group of some of the ...
- 872
3votes
2answers
590views
Find the longest sub string of a word after concatenation of given words array
An Array of N words is given. Each word consists of small letters ('a'-'z'). Our goal is to concatenate the words in such a way as to obtain a single word with longest possible substring composed of ...
2votes
3answers
553views
Recursive palindrome check
I'm trying to solve this which basically calls for a recursive palindrome check with some minor extra steps (Special characters and whitespace can be ignored). The test inputs' length can be 100000 ...
2votes
2answers
3kviews
Given a digit sequence, print the possible decodings of the given digit sequence
Examples: 12 gives: 'AB' and 'L' and 123 gives 'ABC', 'LC' and 'AW' Here is my attempt: ...
- 133
2votes
2answers
6kviews
Find the minimum number of coin change
Description: You are given coins of different denominations and a total amount of money amount. Write a function to compute the fewest number of coins that you need to make up that amount. If that ...
- 5,137
1vote
1answer
499views
Reinterpreting a string, treating < as a backspace character
I've come up with a solution to this coding challenge using recursion. In summary, the input is a string where the < symbol represents a backspace (up to 1 ...
1vote
1answer
126views
Count all possible attendance records with length n, which will be regarded as rewardable
Given a positive integer n, return the number of all possible attendance records with length n, which will be regarded as rewardable. The answer may be very large, return it after \$\mod 10^9 + 7\$. ...
- 261
