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January LeetCoding Challenge 2021 Series' Articles

Back to Ruairí O'Brien's Series
Day1 - Check Array Formation Through Concatenation

Day1 - Check Array Formation Through Concatenation

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2 min read
Week 1 Bonus - Palindrome Permutation

Week 1 Bonus - Palindrome Permutation

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2 min read
Day 2 Find a Corresponding Node of a Binary Tree in a Clone of That Tree

Day 2 Find a Corresponding Node of a Binary Tree in a Clone of That Tree

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Day 3 - Beautiful Arrangement

Day 3 - Beautiful Arrangement

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Day 4 - Merge Two Sorted Lists

Day 4 - Merge Two Sorted Lists

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Day 5 - Remove Duplicates from Sorted List II

Day 5 - Remove Duplicates from Sorted List II

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Day 6 - Kth Missing Positive Number

Day 6 - Kth Missing Positive Number

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Day 7 - Longest Substring Without Repeating Characters

Day 7 - Longest Substring Without Repeating Characters

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Day 8 - Check If Two String Arrays are Equivalent

Day 8 - Check If Two String Arrays are Equivalent

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Day 9 - Word Ladder

Day 9 - Word Ladder

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5 min read
Day 10 - Create Sorted Array through Instructions

Day 10 - Create Sorted Array through Instructions

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4 min read
Day 11 - Merge Sorted Array

Day 11 - Merge Sorted Array

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Day 12 - Add Two Numbers

Day 12 - Add Two Numbers

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Day 13 - Boats to Save People

Day 13 - Boats to Save People

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Day 14 - Minimum Operations to Reduce X to Zero

Day 14 - Minimum Operations to Reduce X to Zero

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Week 2 Bonus - Find Root of N-Ary Tree

Week 2 Bonus - Find Root of N-Ary Tree

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3 min read
Day 15 - Get Maximum in Generated Array

Day 15 - Get Maximum in Generated Array

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Day 16 - Kth Largest Element in an Array

Day 16 - Kth Largest Element in an Array

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Day 17 - Count Sorted Vowel Strings

Day 17 - Count Sorted Vowel Strings

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Day 18 - Max Number of K-Sum Pairs

Day 18 - Max Number of K-Sum Pairs

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Week 3 Bonus - Nested List Weight Sum

Week 3 Bonus - Nested List Weight Sum

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Day 19 - Longest Palindromic Substring

Day 19 - Longest Palindromic Substring

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3 min read
Day 20 - Valid Parentheses

Day 20 - Valid Parentheses

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Day 21 - Find the Most Competitive Subsequence

Day 21 - Find the Most Competitive Subsequence

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Day 22 - Determine if Two Strings Are Close

Day 22 - Determine if Two Strings Are Close

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Day 23 - Sort the Matrix Diagonally

Day 23 - Sort the Matrix Diagonally

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Day 24 - Merge k Sorted Lists

Day 24 - Merge k Sorted Lists

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3 min read
Day 25 - Check If All 1's Are at Least Length K Places Away

Day 25 - Check If All 1's Are at Least Length K Places Away

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Day 28 - Smallest String With A Given Numeric Value

Day 28 - Smallest String With A Given Numeric Value

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Day 27 - Concatenation of Consecutive Binary Numbers

Day 27 - Concatenation of Consecutive Binary Numbers

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1 min read
Day 29 - Vertical Order Traversal of a Binary Tree

Day 29 - Vertical Order Traversal of a Binary Tree

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Day 30 - Minimize Deviation in Array

Day 30 - Minimize Deviation in Array

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Day 31 - Next Permutation

Day 31 - Next Permutation

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