LeetCode

Overview

This repository contains my LeetCode submissions, with entries sorted by:

• Difficulty: Easy, Medium, Hard.
• Question title.

(Note: Rank indicates the percentage of submissions that my code outperforms in terms of runtime.)

The entries are grouped in the following:

Category	Content
Challenges	Blind 75, Grind 75, Grind 169, SQL 45
Courses	AlgoMonster, Grokking Data Structures & Algorithms for Coding Interviews
Topics	Array, Binary Search, Binary Search Tree, Binary Tree, Bit Manipulation, Breadth First Search, Bucket Sort, Counting, Counting Sort, Data Stream, Depth First Search, Design, Divide and Conquer, Dynamic Programming, Enumeration, Geometry, Graph, Greedy, Hash Table, Heap (Priority Queue), Linked List, Math, Matrix, Monotonic Stack, Number Theory, Quick Select, Recursion, Simulation, Sliding Window, Sorting, Stack, String, String Matching, Tree, Trie, Two Pointers, Union Find

Easy

Question	Submission	Runtime	Rank
A Number After a Double Reversal	Java	0ms	100%
Add Binary	Java	2ms	99.94%
Add Digits	Java	0ms	100%
Add Strings	Java	2ms	61.51%
Add Two Integers	Java	0ms	100%
Add to Array-Form of Integer	Java	2ms	99.20%
Alternating Digit Sum	Java	0ms	100%
Apply Operations to an Array	Java	1ms	95.99%
Array Partition	Java	48ms	5.12%
Article Views I	SQL	619ms	51.14%
Average Salary Excluding the Minimum and Maximum Salary	Java	0ms	100%
Average Value of Even Numbers That Are Divisible by Three	Java	0ms	100%
Backspace String Compare	Java	1ms	78.15%
Balanced Binary Tree	Java	0ms	100%
Base 7	Java	1ms	70.47%
Best Time To Buy And Sell Stock	Java	2ms	72.40%
Big Countries	SQL	461ms	66.33%
Biggest Single Number	SQL	406ms	82.18%
Binary Number with Alternating Bits	Java	1ms	11.33%
Binary Search	Java	0ms	100%
Binary Tree Inorder Traversal	Java	0ms	100%
Binary Tree Preorder Traversal	Java	0ms	100%
Binary Tree Postorder Traversal	Java	0ms	100%
Buy Two Chocolates	Java	1ms	100%
Capitalize the Title	Java	3ms	88.41%
Check Balanced String	Java	1ms	99.21%
Check If N And Its Double Exist	Java	2ms	94.12%
Check If Two String Arrays are Equivalent	Java	1ms	59.87%
Check If a Word Occurs As a Prefix of Any Word in a Sentence	Java	0ms	100%
Check Items Matching a Rule	Java	3ms	98.89%
Check if All A's Appears Before All B's	Java	0ms	100%
Check if All Characters Have Equal Number of Occurrences	Java	1ms	100%
Check if Array is Good	Java	2ms	74.84%
Check if Every Row and Column Contains All Numbers	Java	4ms	92.01%
Check if Grid Satisfies Conditions	Java	4ms	92.01%
Check if Matrix Is X-Matrix	Java	0ms	100%
Check if Number Has Equal Digit Count and Digit Value	Java	0ms	100%
Check if Numbers Are Ascending in a Sentence	Java	0ms	100%
Check if The Number is Fascinating	Java	0ms	100%
Check if a String Is an Acronym of Words	Java	1ms	100%
Classes More Than 5 Students	SQL	471ms	96.18%
Combine Two Tables	SQL	629ms	96.12%
Concatenation of Array	Java	1ms	96.28%
Consecutive Characters	Java	1ms	99.83%
Contains Duplicate	Java	7ms	99.29%
Contains Duplicate II	Java	18ms	82.31%
Convert Binary Number in a Linked List to Integer	Java	0ms	100%
Convert Date to Binary	Java	4ms	66.45%
Convert the Temperature	Java	0ms	100%
Count Common Words With One Occurrence	Java	6ms	89.98%
Count Elements With Maximum Frequency	Java	1ms	99.75%
Count Equal and Divisible Pairs in an Array	Java	3ms	99.52%
Count Integers With Even Digit Sum	Java	1ms	86.87%
Count Largest Group	Java	3ms	96.75%
Count Negative Numbers in a Sorted Matrix	Java	0ms	100%
Count Number of Pairs With Absolute Difference K	Java	4ms	95.49%
Count Pairs Of Similar Strings	Java	58ms	41.34%
Count Symmetric Integers	Java	44ms	25.05%
Count the Digits That Divide a Number	Java	0ms	100%
Count the Number of Consistent Strings	Java	6ms	86.92%
Count the Number of Special Characters I	Java	1ms	100%
Counting Bits	Java	2ms	95%
Counting Words With a Given Prefix Occurrence	Java	0ms	100%
Customers Placing The Largest Number Of Orders	SQL	799ms	87.57%
Customers Who Never Order	SQL	908ms	93.29%
Design HashMap	Java	32ms	39.02%
Design HashSet	Java	12ms	97.83%
Design an Ordered Stream	Java	76ms	99.56%
Destination City	Java	2ms	100%
Detect Capital	Java	0ms	100%
Difference Between Element Sum and Digit Sum of an Array	Java	2ms	98.35%
Distribute Candies	Java	31ms	55.24%
Duplicate Emails	SQL	865ms	11.83%
Employee Bonus	SQL	1659ms	64.38%
Employees Earning More Than Their Managers	SQL	1429ms	10.98%
Faulty Keyboard	Java	3ms	98.26%
Fibonacci Number	Java	0ms	100%
Final Prices With a Special Discount in a Shop	Java	2ms	65.61%
Final Value of Variable After Performing Operations	Java	1ms	74.56%
Find All Numbers Disappeared in an Array	Java	3ms	99.85%
Find Center of Star Graph	Java	3ms	34.14%
Find Closest Number to Zero	Java	2ms	85.90%
Find Common Elements Between Two Arrays	Java	1ms	100%
Find First Palindromic String in the Array	Java	1ms	100%
Find Greatest Common Divisor of Array	Java	0ms	100%
Find Indices of Stable Mountains	Java	1ms	100%
Find Lucky Integer in an Array	Java	1ms	100%
Find Mode in Binary Search Tree	Java	6ms	44.33%
Find Numbers with Even Number of Digits	Java	1ms	98.93%
Find Pivot Index	Java	1ms	94.56%
Find Resultant Array After Removing Anagrams	Java	5ms	14.27%
Find Smallest Letter Greater Than Target	Java	0ms	100%
Find Subsequence of Length K With the Largest Sum	Java	8ms	62.37%
Find Target Indices After Sorting Array	Java	0ms	100%
Find Valid Pair of Adjacent Digits in String	Java	2ms	88.14%
Find Words Containing Character	Java	2ms	54.27%
Find Words That Can Be Formed by Characters	Java	5ms	87.08%
Find if Digit Game Can Be Won	Java	0ms	100%
Find if Path Exists in Graph	Java	53ms	88.29%
Find the Difference	Java	2ms	62.27%
Find the Difference of Two Arrays	Java	11ms	45.10%
Find the Distinct Difference Array	Java	5ms	93.20%
Find the Highest Altitude	Java	0ms	100%
Find the Index of the First Occurrence in a String	Java	0ms	100%
Find the Middle Index in Array	Java	0ms	100%
Find the Number of Good Pairs I	Java	1ms	100%
Find the Peaks	Java	1ms	100%
Find the Town Judge	Java	2ms	100%
First Bad Version	Java	24ms	98.13%
First Letter to Appear Twice	Java	0ms	100%
First Unique Character in a String	Java	5ms	93.93%
FizzBuzz	Java	1ms	99.52%
Generate a String With Characters That Have Odd Counts	Java	1ms	83.40%
Greatest English Letter in Upper and Lower Case	Java	4ms	72.30%
Guess Number Higher or Lower	Java	0ms	100%
Happy Number	Java	0ms	100%
Harshad Number	Java	0ms	100%
Height Checker	Java	2ms	88.86%
How Many Numbers Are Smaller Than the Current Number	Java	5ms	83.20%
Implement Queue Using Stacks	Java	0ms	100%
Implement Stack Using Queues	Java	0ms	100%
Increasing Order Search Tree	Java	0ms	100%
Intersection of Multiple Arrays	Java	2ms	100%
Intersection of Two Arrays	Java	1ms	98.70%
Intersection of Two Arrays II	Java	1ms	98.45%
Invert Binary Tree	Java	0ms	100%
Is Subsequence	Java	1ms	93.37%
Isomorphic Strings	Java	13ms	52.01%
Jewels and Stones	Java	1ms	60.50%
K Items With the Maximum Sum	Java	1ms	89.54%
Keep Multiplying Found Values by Two	Java	0ms	100%
Keyboard Row	Java	0ms	100%
Kids With the Greatest Number of Candies	Java	1ms	87.73%
Kth Distinct String in an Array	Java	6ms	86.06%
Kth Largest Element in a Stream	Java	21ms	54.99%
Kth Missing Positive Number	Java	2ms	11.57%
Largest Number At Least Twice of Others	Java	0ms	100%
Largest Odd Number in String	Java	1ms	99.64%
Largest Positive Integer That Exists With Its Negative	Java	6ms	61.28%
Largest Triangle Area	Java	4ms	99.15%
Last Stone Weight	Java	1ms	97.76%
Left and Right Sum Differences	Java	2ms	98.18%
Length of Last Word	Java	1ms	33.68%
Linked List Cycle	Java	0ms	100%
Longest Common Prefix	Java	1ms	64.40%
Longest Palindrome	Java	7ms	52.78%
Majority Element	Java	2ms	99.80%
Make Array Zero by Subtracting Equal Amounts	Java	0ms	100%
Make The String Great	Java	3ms	62.40%
Matrix Diagonal Sum	Java	0ms	100%
Max Consecutive Ones	Java	2ms	93.86%
Max Pair Sum in an Array	Java	3ms	93.95%
Maximum Count of Positive Integer and Negative Integer	Java	0ms	100%
Maximum Depth of Binary Tree	Java	0ms	100%
Maximum Difference Between Even and Odd Frequency I	Java	1ms	100%
Maximum Number of Balloons	Java	3ms	75.90%
Maximum Product Difference Between Two Pairs	Java	2ms	98.79%
Maximum Product of Three Numbers	Java	11ms	84.46%
Maximum Product of Two Elements in an Array	Java	0ms	100%
Maximum Sum With Exactly K Elements	Java	1ms	100%
Maximum Units on a Truck	Java	8ms	95.90%
Mean of Array After Removing Some Elements	Java	11ms	5.94%
Merge Sorted Array	Java	1ms	29.79%
Merge Two Binary Trees	Java	0ms	100%
Merge Two Sorted Lists	Java	0ms	100%
Middle of the Linked List	Java	0ms	100%
Minimize String Length	Java	3ms	100%
Minimum Absolute Difference in BST	Java	0ms	100%
Minimum Average of Smallest and Largest Elements	Java	2ms	97.31%
Minimum Common Value	Java	2ms	86.22%
Minimum Distance Between BST Nodes	Java	0ms	100%
Minimum Element After Replacement With Digit Sum	Java	1ms	100%
Minimum Operations to Exceed Threshold Value I	Java	0ms	100%
Minimum Sum of Mountain Triplets I	Java	1ms	100%
Missing Number	Java	0ms	100%
Monotonic Stack	Java	1ms	98.82%
Most Common Word	Java	17ms	43.61%
Most Frequent Even Element	Java	12ms	93.70%
Most Frequent Number Following Key In an Array	Java	1ms	100%
Move Zeroes	Java	1ms	99.85%
Neither Minimum nor Maximum	Java	4ms	99.50%
Next Greater Element I	Java	3ms	92.50%
Not Boring Movies	SQL	495ms	47.80%
Number of 1 Bits	Java	0ms	100%
Number of Common Factors	Java	1ms	44.28%
Number of Different Integers in a String	Java	3ms	78.75%
Number of Distinct Averages	Java	1ms	99.35%
Number of Employees Who Met the Target	Java	0ms	100%
Number of Good Pairs	Java	0ms	100%
Number of Senior Citizens	Java	0ms	100%
Palindrome Linked List	Java	4ms	83.80%
Palindrome Number	Java	6ms	30.91%
Path Sum	Java	0ms	100%
Percentage of Letter in String	Java	0ms	100%
Perfect Number	Java	2ms	83.64%
Permutation Difference between Two Strings	Java	1ms	100%
Plus One	Java	0ms	100%
Power of Four	Java	0ms	100%
Power of Three	Java	7ms	100%
Power of Two	Java	0ms	100%
Prime Number of Set Bits in Binary Representation	Java	66ms	10.43%
Product Sales Analysis I	SQL	1896ms	83.84%
Project Employees I	SQL	1032ms	62.20%
Range Sum Query - Immutable	Java	8ms	65.10%
Range Sum of BST	Java	1ms	45.33%
Rank Transform of an Array	Java	25ms	86.01%
Ransom Note	Java	1ms	99.14%
Relative Ranks	Java	9ms	61.66%
Remove All Adjacent Duplicates In String	Java	36ms	48.71%
Remove Duplicates from Sorted Array	Java	1ms	64.98%
Remove Duplicates from Sorted List	Java	0ms	100%
Remove Element	Java	0ms	100%
Remove Linked List Elements	Java	1ms	94%
Remove Trailing Zeros From a String	Java	1ms	100%
Reverse Linked List	Java	0ms	100%
Reverse String	Java	0ms	100%
Reverse Vowels of a String	Java	4ms	50.91%
Richest Customer Wealth	Java	0ms	100%
Row With Maximum Ones	Java	5ms	27.61%
Running Sum of 1d Array	Java	0ms	100%
Same Tree	Java	0ms	100%
Score of a String	Java	1ms	99.49%
Search Insert Position	Java	0ms	100%
Search in a Binary Search Tree	Java	0ms	100%
Second Largest Digit in a String	Java	1ms	95.03%
Second Minimum Node In a Binary Tree	Java	0ms	100%
Self Dividing Numbers	Java	1ms	100%
Separate the Digits in an Array	Java	5ms	74.92%
Set Mismatch	Java	2ms	95.73%
Sign of the Product of an Array	Java	0ms	100%
Smallest Divisible Digit Product I	Java	1ms	65.70%
Smallest Even Multiple	Java	0ms	100%
Smallest Missing Integer Greater Than Sequential Prefix Sum	Java	1ms	92.66%
Sort Array by Increasing Frequency	Java	5ms	92.79%
Sort Integers by The Number of 1 Bits	Java	7ms	74.98%
Sort the People	Java	5ms	97.38%
Sorting the Sentence	Java	0ms	100%
Sqrt(x)	Java	1ms	87.09%
Squares of a Sorted Array	Java	1ms	100%
Subtract the Product and Sum of Digits of an Integer	Java	0ms	100%
Sum Multiples	Java	3ms	63.36%
Sum of Digits in Base K	Java	0ms	100%
Sum of Digits of String After Convert	Java	2ms	50.64%
Sum of Squares of Special Elements	Java	1ms	100%
Sum of Unique Elements	Java	0ms	100%
Take Gifts From the Richest Pile	Java	6ms	52.37%
Third Maximum Number	Java	1ms	97.13%
Three Consecutive Odds	Java	0ms	100%
Three Divisors	Java	1ms	61.86%
To Lower Case	Java	0ms	100%
Two Sum	Java	1ms	98.89%
Two Sum IV - Input is a BST	Java	1ms	96.19%
Ugly Number	Java	0ms	100%
Uncommon Words from Two Sentences	Java	3ms	50.44%
Unique Number of Occurrences	Java	2ms	97.94%
Valid Anagram	Java	2ms	97.84%
Valid Mountain Array	Java	2ms	71.67%
Valid Palindrome	Java	2ms	99.08%
Valid Palindrome II	Java	4ms	99.71%
Valid Parentheses	Java	2ms	97.66%
Valid Perfect Square	Java	0ms	100%
Valid Word	Java	1ms	99.05%
Word Pattern	Java	1ms	82.52%
XOR Operation in an Array	Java	0ms	100%
Zigzag Grid Traversal With Skip	Java	1ms	100%

Medium

Question	Submission	Runtime	Rank
Add Two Numbers	Java	1ms	100%
Check if Number is a Sum of Powers of Three	Java	0ms	100%
Container With Most Water	Java	5ms	74.40%
Count Primes	Java	94ms	82.87%
Count the Number of Special Characters II	Java	35ms	49.81%
Daily Temperatures	Java	77ms	31.05%
Divide Two Integers	Java	4ms	5.52%
Find All Anagrams in a String	Java	9ms	91.31%
Find First and Last Position of Element in Sorted Array	Java	0ms	100%
Find Good Days to Rob the Bank	Java	5ms	88.83%
Find Minimum in Rotated Sorted Array	Java	0ms	100%
Find Peak Element	Java	0ms	100%
Find the Duplicate Number	Java	4ms	88.06%
Find the Kth Largest Integer in the Array	Java	79ms	50.60%
Finding Pairs With a Certain Sum	Java	153ms	42.39%
Group Anagrams	Java	9ms	35.78%
Implement Trie (Prefix Tree)	Java	33ms	85.89%
Insert Delete GetRandom O(1)	Java	25ms	93.59%
Kth Largest Element in an Array	Java	39ms	73.11%
Kth Smallest Element In A Sorted Matrix	Java	15ms	55.37%
Kth Smallest Element in a BST	Java	0ms	100%
Longest Substring Without Repeated Characters	Java	6ms	70.55%
Majority Element II	Java	10ms	45.32%
Maximal Score After Applying K Operations	Java	164ms	13.81%
Maximum Sum of Distinct Subarrays With Length K	Java	54ms	30.96%
Min Stack	Java	4ms	97.18%
Minimum Number of Vertices to Reach All Nodes	Java	8ms	99.23%
Minimum Operations to Exceed Threshold Value II	Java	146ms	71.53%
Minimum Operations to Half Array Sum	Java	198ms	74.18%
Minimum Sum of Mountain Triplets II	Java	2ms	100%
Next Greater Element II	Java	9ms	94.03%
Number of Provinces	Java	1ms	88.40%
Peak Index in a Mountain Array	Java	0ms	100%
Product of Array Except Self	Java	2ms	89.32%
Remove Duplicates from Sorted List II	Java	3ms	9.87%
Remove Stones to Minimize the Total	Java	600ms	20.43%
Removing Stars From a String	Java	87ms	32.57%
Reverse Integer	Java	0ms	100%
Search in Rotated Sorted Array	Java	0ms	100%
Search in Rotated Sorted Array II	Java	0ms	100%
Second Highest Salary	SQL	480ms	64.38%
Set Matrix Zeroes	Java	1ms	73.86%
Simplify Path	Java	5ms	51.87%
Smallest Number in Infinite Set	Java	16ms	33.15%
Sort Characters By Frequency	Java	14ms	64.64%
Sort Colors	Java	0ms	100%
Sort List	Java	42ms	5%
Sort an Array	Java	41ms	26.79%
Spiral Matrix	Java	0ms	100%
Sum of Square Numbers	Java	3ms	93.35%
Sum of Two Integers	Java	0ms	100%
Swap Nodes in Pairs	Java	0ms	100%
Top K Frequent Elements	Java	14ms	58.56%
Top K Frequent Words	Java	6ms	98%
Two Input Sum II - Input Array Is Sorted	Java	2ms	93.40%
Ugly Number II	Java	2ms	98.25%
Validate Binary Search Tree	Java	2ms	98.25%

Hard

Question	Submission	Runtime	Rank
Find Median from Data Stream	Java	92ms	78.28%
Find in Mountain Array	Java	0ms	100%
First Missing Positive	Java	1ms	100%
Merge k Sorted Lists	Java	5ms	35.39%
Number of Visible People in a Queue	Java	63ms	34.82%