Math LeetCode Problems: All 485,
With Python Solutions

Every problem in this library that LeetCode tags Math. 413 of them carry a complete Python solution, a worked example and the time and space complexity of the approach.

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Easy: 121
Medium: 244
Hard: 120

1 pattern

How Math problems are solved

A tag names the subject, not the method. These pattern hubs cover the techniques that actually solve Math problems — each one explains the approach, gives a Python template and states its complexity.

Math and Number TheoryFind the closed form, the invariant, or the modular identity — and skip the loop entirely.

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python

Please analyze this context and help me answer the question or solve the problem.

Technical interview · 45 minsolution.pyShared editor · Python 3Longest substring without repeatsMediumGiven a string s, return the length of the longest contiguous substring in which every character is unique.s = "abcabcbb"
→ 31def length_of_longest_substring(s: str) -> int:2 last_seen = {}3 left = best = 04 for right, ch in enumerate(s):5 if ch in last_seen and last_seen[ch] >= left:

python

def length_of_longest_substring(s: str) -> int:    last_seen = {}                    # char -> index    left = best = 0    for right, ch in enumerate(s):        if ch in last_seen and last_seen[ch] >= left:            left = last_seen[ch] + 1  # jump past it        last_seen[ch] = right        best = max(best, right - left + 1)    return best    last_seen = {}                    # char -> index

Approach

At each index r, the window's left edge is:

left r = max (left r -1, last[s r] + 1)

Time O(n): each character enters and leaves the window once.
Space O(min(n, k)): k is the size of the character set.

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python

Please analyze this context and help me answer the question or solve the problem.

python

def length_of_longest_substring(s: str) -> int:    last_seen = {}                    # char -> index    left = best = 0    for right, ch in enumerate(s):        if ch in last_seen and last_seen[ch] >= left:            left = last_seen[ch] + 1  # jump past it        last_seen[ch] = right        best = max(best, right - left + 1)    return best    last_seen = {}                    # char -> index

Approach

At each index r, the window's left edge is:

left r = max (left r -1, last[s r] + 1)

Time O(n): each character enters and leaves the window once.
Space O(min(n, k)): k is the size of the character set.

Type your message...

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QuitEscHide+QCapture+PCrop+OSubmit+EnterPress to get answerLeft/Right+Up/Down+

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python

Please analyze this context and help me answer the question or solve the problem.

python

def length_of_longest_substring(s: str) -> int:    last_seen = {}                    # char -> index    left = best = 0    for right, ch in enumerate(s):        if ch in last_seen and last_seen[ch] >= left:            left = last_seen[ch] + 1  # jump past it        last_seen[ch] = right        best = max(best, right - left + 1)    return best    last_seen = {}                    # char -> index

Approach

At each index r, the window's left edge is:

left r = max (left r -1, last[s r] + 1)

Time O(n): each character enters and leaves the window once.
Space O(min(n, k)): k is the size of the character set.

Type your message...

GPT-6.1 TerraClear chat

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QuitEscHide+QCapture+PCrop+OSubmit+EnterPress to get answerLeft/Right+Up/Down+

Math problems by difficulty

Showing the first 200 of 485 problems. Problems with a complete Python solution are listed first, then by ascending problem number.

Easy (57)

Easy problems
No.	Problem	Topics
0009	Palindrome Number	Math
0013	Roman to Integer	Hash Table, Math, String
0066	Plus One	Array, Math
0067	Add Binary	Bit Manipulation, Math, String +1
0069	Sqrt(x)	Math, Binary Search
0070	Climbing Stairs	Memoization, Math, Dynamic Programming
0168	Excel Sheet Column Title	Math, String
0171	Excel Sheet Column Number	Math, String
0202	Happy Number	Hash Table, Math, Two Pointers
0231	Power of Two	Bit Manipulation, Recursion, Math
0258	Add Digits	Math, Number Theory, Simulation
0263	Ugly Number	Math
0268	Missing Number	Bit Manipulation, Array, Hash Table +3
0292	Nim Game	Brainteaser, Math, Game Theory
0326	Power of Three	Recursion, Math
0342	Power of Four	Bit Manipulation, Recursion, Math
0367	Valid Perfect Square	Math, Binary Search
0405	Convert a Number to Hexadecimal	Bit Manipulation, Math, String
0412	Fizz Buzz	Math, String, Simulation
0415	Add Strings	Math, String, Simulation
0441	Arranging Coins	Math, Binary Search
0492	Construct the Rectangle	Math
0504	Base 7	Math, String
0507	Perfect Number	Math
0509	Fibonacci Number	Recursion, Memoization, Math +1
0598	Range Addition II	Array, Math
0628	Maximum Product of Three Numbers	Array, Math, Sorting
0728	Self Dividing Numbers	Math
0762	Prime Number of Set Bits in Binary Representation	Bit Manipulation, Math
0812	Largest Triangle Area	Geometry, Array, Math
0836	Rectangle Overlap	Geometry, Math
0883	Projection Area of 3D Shapes	Geometry, Array, Math +1
0892	Surface Area of 3D Shapes	Geometry, Array, Math +1
0908	Smallest Range I	Array, Math
0914	X of a Kind in a Deck of Cards	Array, Hash Table, Math +2
0976	Largest Perimeter Triangle	Greedy, Array, Math +1
0989	Add to Array-Form of Integer	Array, Math
1025	Divisor Game	Brainteaser, Math, Dynamic Programming +1
1030	Matrix Cells in Distance Order	Geometry, Array, Math +2
1037	Valid Boomerang	Geometry, Array, Math
1071	Greatest Common Divisor of Strings	Math, String
1103	Distribute Candies to People	Math, Simulation
1137	N-th Tribonacci Number	Memoization, Math, Dynamic Programming
1154	Day of the Year	Math, String
1175	Prime Arrangements	Math
1185	Day of the Week	Math
1217	Minimum Cost to Move Chips to The Same Position	Greedy, Array, Math
1232	Check If It Is a Straight Line	Geometry, Array, Math
1252	Cells with Odd Values in a Matrix	Array, Math, Simulation
1266	Minimum Time Visiting All Points	Geometry, Array, Math
1281	Subtract the Product and Sum of Digits of an Integer	Math
1290	Convert Binary Number in a Linked List to Integer	Linked List, Math
1295	Find Numbers with Even Number of Digits	Array, Math
1304	Find N Unique Integers Sum up to Zero	Array, Math
1317	Convert Integer to the Sum of Two No-Zero Integers	Math
1323	Maximum 69 Number	Greedy, Math
1342	Number of Steps to Reduce a Number to Zero	Bit Manipulation, Math

Medium (103)

Medium problems
No.	Problem	Topics
0002	Add Two Numbers	Recursion, Linked List, Math
0007	Reverse Integer	Math
0012	Integer to Roman	Hash Table, Math, String
0029	Divide Two Integers	Bit Manipulation, Math
0043	Multiply Strings	Math, String, Simulation
0048	Rotate Image	Array, Math, Matrix
0050	Pow(x, n)	Recursion, Math
0062	Unique Paths	Math, Dynamic Programming, Combinatorics
0089	Gray Code	Bit Manipulation, Math, Backtracking
0096	Unique Binary Search Trees	Tree, Binary Search Tree, Math +2
0150	Evaluate Reverse Polish Notation	Stack, Array, Math
0166	Fraction to Recurring Decimal	Hash Table, Math, String
0172	Factorial Trailing Zeroes	Math
0189	Rotate Array	Array, Math, Two Pointers
0204	Count Primes	Array, Math, Enumeration +1
0223	Rectangle Area	Geometry, Math
0227	Basic Calculator II	Stack, Math, String
0241	Different Ways to Add Parentheses	Recursion, Memoization, Math +2
0264	Ugly Number II	Hash Table, Math, Dynamic Programming +1
0279	Perfect Squares	Breadth-First Search, Math, Dynamic Programming
0313	Super Ugly Number	Array, Math, Dynamic Programming
0319	Bulb Switcher	Brainteaser, Math
0343	Integer Break	Math, Dynamic Programming
0357	Count Numbers with Unique Digits	Math, Dynamic Programming, Backtracking
0365	Water and Jug Problem	Depth-First Search, Breadth-First Search, Math
0368	Largest Divisible Subset	Array, Math, Dynamic Programming +1
0371	Sum of Two Integers	Bit Manipulation, Math
0372	Super Pow	Math, Divide and Conquer
0375	Guess Number Higher or Lower II	Math, Dynamic Programming, Game Theory
0380	Insert Delete GetRandom O(1)	Design, Array, Hash Table +2
0382	Linked List Random Node	Reservoir Sampling, Linked List, Math +1
0384	Shuffle an Array	Design, Array, Math +1
0390	Elimination Game	Recursion, Math
0396	Rotate Function	Array, Math, Dynamic Programming
0398	Random Pick Index	Reservoir Sampling, Hash Table, Math +1
0400	Nth Digit	Math, Binary Search
0423	Reconstruct Original Digits from English	Hash Table, Math, String
0445	Add Two Numbers II	Stack, Linked List, Math
0447	Number of Boomerangs	Array, Hash Table, Math
0453	Minimum Moves to Equal Array Elements	Array, Math
0462	Minimum Moves to Equal Array Elements II	Array, Math, Sorting
0464	Can I Win	Bit Manipulation, Memoization, Math +3
0470	Implement Rand10() Using Rand7()	Math, Rejection Sampling, Probability and Statistics +1
0477	Total Hamming Distance	Bit Manipulation, Array, Math
0478	Generate Random Point in a Circle	Geometry, Math, Rejection Sampling +1
0486	Predict the Winner	Recursion, Array, Math +2
0497	Random Point in Non-overlapping Rectangles	Reservoir Sampling, Array, Math +4
0519	Random Flip Matrix	Reservoir Sampling, Hash Table, Math +1
0523	Continuous Subarray Sum	Array, Hash Table, Math +1
0528	Random Pick with Weight	Array, Math, Binary Search +2
0537	Complex Number Multiplication	Math, String, Simulation
0539	Minimum Time Difference	Array, Math, String +1
0553	Optimal Division	Array, Math, Dynamic Programming
0556	Next Greater Element III	Math, Two Pointers, String
0592	Fraction Addition and Subtraction	Math, String, Simulation
0593	Valid Square	Geometry, Math
0633	Sum of Square Numbers	Math, Two Pointers, Binary Search
0640	Solve the Equation	Math, String, Simulation
0650	2 Keys Keyboard	Math, Dynamic Programming
0667	Beautiful Arrangement II	Array, Math
0670	Maximum Swap	Greedy, Math
0672	Bulb Switcher II	Bit Manipulation, Depth-First Search, Breadth-First Search +1
0738	Monotone Increasing Digits	Greedy, Math
0754	Reach a Number	Math, Binary Search
0775	Global and Local Inversions	Array, Math
0779	K-th Symbol in Grammar	Bit Manipulation, Recursion, Math
0781	Rabbits in Forest	Greedy, Array, Hash Table +1
0788	Rotated Digits	Math, Dynamic Programming
0789	Escape The Ghosts	Array, Math
0808	Soup Servings	Math, Dynamic Programming, Probability and Statistics
0837	New 21 Game	Math, Dynamic Programming, Sliding Window +1
0840	Magic Squares In Grid	Array, Hash Table, Math +1
0858	Mirror Reflection	Geometry, Math, Number Theory
0866	Prime Palindrome	Math, Number Theory
0869	Reordered Power of 2	Hash Table, Math, Counting +2
0877	Stone Game	Array, Math, Dynamic Programming +1
0910	Smallest Range II	Greedy, Array, Math +1
0932	Beautiful Array	Array, Math, Divide and Conquer
0939	Minimum Area Rectangle	Geometry, Array, Hash Table +2
0963	Minimum Area Rectangle II	Geometry, Array, Hash Table +1
0970	Powerful Integers	Hash Table, Math, Enumeration
0973	K Closest Points to Origin	Geometry, Array, Math +4
0991	Broken Calculator	Greedy, Math
1006	Clumsy Factorial	Stack, Math, Simulation
1015	Smallest Integer Divisible by K	Hash Table, Math
1017	Convert to Base -2	Math
1033	Moving Stones Until Consecutive	Brainteaser, Math
1040	Moving Stones Until Consecutive II	Array, Math, Sorting +1
1041	Robot Bounded In Circle	Math, String, Simulation
1073	Adding Two Negabinary Numbers	Array, Math
1093	Statistics from a Large Sample	Array, Math, Probability and Statistics
1104	Path In Zigzag Labelled Binary Tree	Tree, Math, Binary Tree
1131	Maximum of Absolute Value Expression	Array, Math
1140	Stone Game II	Array, Math, Dynamic Programming +2
1201	Ugly Number III	Math, Binary Search, Combinatorics +1
1227	Airplane Seat Assignment Probability	Brainteaser, Math, Dynamic Programming +1
1237	Find Positive Integer Solution for a Given Equation	Math, Two Pointers, Binary Search +1
1238	Circular Permutation in Binary Representation	Bit Manipulation, Math, Backtracking
1247	Minimum Swaps to Make Strings Equal	Greedy, Math, String
1248	Count Number of Nice Subarrays	Array, Hash Table, Math +2
1276	Number of Burgers with No Waste of Ingredients	Math
1344	Angle Between Hands of a Clock	Math
1352	Product of the Last K Numbers	Design, Array, Math +2

Hard (40)

Hard problems
No.	Problem	Topics
0060	Permutation Sequence	Recursion, Math
0149	Max Points on a Line	Geometry, Array, Hash Table +1
0224	Basic Calculator	Stack, Recursion, Math +1
0233	Number of Digit One	Recursion, Math, Dynamic Programming
0273	Integer to English Words	Recursion, Math, String
0282	Expression Add Operators	Math, String, Backtracking
0335	Self Crossing	Geometry, Array, Math
0381	Insert Delete GetRandom O(1) - Duplicates allowed	Design, Array, Hash Table +2
0391	Perfect Rectangle	Geometry, Array, Hash Table +2
0458	Poor Pigs	Math, Dynamic Programming, Combinatorics
0479	Largest Palindrome Product	Math, Enumeration
0483	Smallest Good Base	Math, Binary Search
0564	Find the Closest Palindrome	Math, String
0587	Erect the Fence	Geometry, Array, Math
0668	Kth Smallest Number in Multiplication Table	Math, Binary Search
0679	24 Game	Array, Math, Backtracking
0710	Random Pick with Blacklist	Array, Hash Table, Math +3
0780	Reaching Points	Math
0782	Transform to Chessboard	Bit Manipulation, Array, Math +1
0793	Preimage Size of Factorial Zeroes Function	Math, Binary Search
0805	Split Array With Same Average	Bit Manipulation, Array, Math +2
0810	Chalkboard XOR Game	Bit Manipulation, Brainteaser, Array +2
0829	Consecutive Numbers Sum	Math, Enumeration
0878	Nth Magical Number	Math, Binary Search
0887	Super Egg Drop	Math, Binary Search, Dynamic Programming
0891	Sum of Subsequence Widths	Array, Math, Sorting
0899	Orderly Queue	Math, String, Sorting
0902	Numbers At Most N Given Digit Set	Array, Math, String +2
0906	Super Palindromes	Math, String, Enumeration
0913	Cat and Mouse	Graph, Topological Sort, Memoization +3
0920	Number of Music Playlists	Math, Dynamic Programming, Combinatorics
0927	Three Equal Parts	Array, Math
0952	Largest Component Size by Common Factor	Union Find, Array, Hash Table +2
0964	Least Operators to Express Number	Memoization, Math, Dynamic Programming
0996	Number of Squareful Arrays	Bit Manipulation, Array, Hash Table +4
1012	Numbers With Repeated Digits	Math, Dynamic Programming
1250	Check If It Is a Good Array	Array, Math, Number Theory
1307	Verbal Arithmetic Puzzle	Array, Math, String +1
1330	Reverse Subarray To Maximize Array Value	Greedy, Array, Math
1359	Count All Valid Pickup and Delivery Options	Math, Dynamic Programming, Combinatorics

How Math problems are solved

When the Math problem arrives live.

Approach

Approach

Approach

Math problems by difficulty

Easy (57)57

Medium (103)103

Hard (40)40

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Easy (57)

Medium (103)

Hard (40)