All Questions
Tagged with combinatorics programming-challenge
70 questions
1
vote
1
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109
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Finding the number of distinct decompositions a number has using only repdigits
This is a problem from a previous semester that I am trying to upsolve. I am trying to solve a problem involving the total number of ways of decomposing a number using only repdigits. A repdigit is a ...
- 59
7
votes
2
answers
1k
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Find all combinations of length 3 whose sum is divisible by a given number
I came up with a suitable solution to a HackerRank problem that failed because the execution took longer than 10 seconds on lists that were of very large size.
The problem: Given a list ...
2
votes
2
answers
804
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Subarrays with length
You are given an array A of length N (where N is as large as 2×105). All elements of the array are positive integers less than or equal to N. Determine the count of subarrays (contiguous subsequences) ...
1
vote
2
answers
376
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Next different permutation in C
This is a program which you can get the next "different", i.e. elements in A[] can be identical, permutation at each call. I've written a C++ program for ...
- 541
8
votes
3
answers
326
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Refactor the code which performs "cross-product", "reduce", "product of list" and "sum of list"
I have come up with a sequence of steps to find the maximum product of y positive numbers which add up to x. But the program is ...
- 227
7
votes
2
answers
1k
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Letter Combinations of a phone number using a Dictionary
Problem statement (online source)
Given a digit string, return all possible letter combinations that the
number could represent.
A mapping of digit to letters (just like on the telephone ...
- 103
11
votes
1
answer
2k
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Earliest time frog can jump to the other side of a river in C#
I'm new to C#, I programmed a little in Java in the past. I had the two previous exercises reviewed here (permCheck, cyclicRotation, with a 100% score, just like this one), and I'm applying what the ...
- 889
6
votes
2
answers
2k
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Codility's Permutation Check in C#
I've made a few things in Java, and now I'm learning C#.
The code passes the tests with 100% final score. I want to know what things can be improved in my code.
Task description
A non-empty array ...
- 889
2
votes
2
answers
575
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Counting block combinations I: Project Euler 114
Problem statement (For more detailed description (including pictures), please, visit the link):
A row measuring seven units in length has red blocks with a minimum
length of three units placed on ...
- 719
4
votes
1
answer
655
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Counting Bouncy Numbers: Project Euler #113
Problem statement:
Working from left-to-right if no digit is exceeded by the digit to its
left it is called an increasing number; for example, 134468.
Similarly if no digit is exceeded by the ...
- 719
2
votes
3
answers
3k
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Counting numbers that are divisible by 3 and can be produced from the digits of a given number
I'm trying to solve this problem from codewars.
Problem
Given a certain number, how many multiples of three could you obtain with its digits? Suppose that you have the number ...
- 175
11
votes
3
answers
991
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Print sums of all subsets
Print sums of all subsets of a given set
Problem summary : Print all subset sums of a given set of integers
My approach is to store previous results and use them to calculate new (similar idea as DP).
...
- 213
3
votes
2
answers
354
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Challenge: phone keypad to letters - return all possible strings
The challenge:
Given a mapping of digits to letters (as in a phone number), and a digit string, return all possible letters the number could represent. You can assume each valid number in the ...
- 855
2
votes
2
answers
986
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Project Euler # 24 Lexicographic permutations in Python
A permutation is an ordered arrangement of objects. For example, 3124 is one possible permutation of
the digits 1, 2, 3 and 4. If all of the permutations are listed numerically or alphabetically, we ...
user203258
4
votes
2
answers
772
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Letter case permutation
The question can be found here https://leetcode.com/problems/letter-case-permutation
Given a string S, we can transform every letter individually to be
lowercase or uppercase to create another ...
user172231