递归

两数相加

Add Two Numbers requires careful linked-list pointer manipulation to sum digits while handling carries efficiently in in…

正则表达式匹配

The Regular Expression Matching problem involves checking if a string matches a pattern using '.' and '*'.

合并两个有序链表

Merge two sorted linked lists by splicing nodes into one sorted list using linked-list pointer manipulation and recursio…

两两交换链表中的节点

Learn how to swap every adjacent linked-list pair by rewiring nodes safely without changing values or breaking the remai…

K 个一组翻转链表

Reverse Nodes in k-Group challenges you to reverse segments of a linked list in groups of size k.

通配符匹配

Implement full wildcard pattern matching using '?' and '*' by applying state transition dynamic programming with careful…

Pow(x, n)

Calculate x to the power n efficiently using recursion and exponentiation, handling negative powers and large inputs saf…

排列序列

Find the kth permutation sequence of a set of numbers using math and recursion to efficiently compute the result.

重排链表

Reorder List requires careful pointer manipulation in a singly linked list to interleave nodes from the ends without alt…

移除链表元素

Remove all nodes from a linked list that have a specific value, adjusting pointers to preserve the rest of the list.

反转链表

Reverse a singly linked list in place, converting the head to tail, with an iterative or recursive approach.

基本计算器

Implement a basic calculator to evaluate mathematical expressions, ensuring correct evaluation with stack-based manageme…

2 的幂

Determine if a given integer is a power of two using efficient math and bit manipulation techniques with optional recurs…

数字 1 的个数

Compute the total number of digit one appearing in all numbers from 0 up to n using state transition dynamic programming…

回文链表

Solve Palindrome Linked List by finding the midpoint, reversing the second half, and comparing mirrored nodes in linear …

为运算表达式设计优先级

Solve Different Ways to Add Parentheses by splitting on each operator and memoizing every subexpression result list.

整数转换英文表示

Convert a given integer to its English words representation using mathematical logic and string manipulation.

3 的幂

Determine if a given integer is a power of three using math and recursion techniques.

4的幂

Determine if a given integer is a power of four using math insights and bit manipulation tricks efficiently in code.

消除游戏

Elimination Game uses a systematic removal of numbers with alternating left-right passes, solvable with math and recursi…

字符串解码

Decode a nested encoded string using stack-based state management, handling repeated patterns efficiently with recursion…

预测赢家

Predict the Winner involves two players taking turns to maximize their score by picking from either end of an array, opt…

斐波那契数

Calculate the nth Fibonacci number using state transition dynamic programming and recursive techniques efficiently in in…

Lisp 语法解析

Parse Lisp expressions using stack-based state management to evaluate variables and operations.

特殊的二进制字符串

Solve the Special Binary String problem using string manipulation and recursion, optimizing lexicographical order.

基本计算器 IV

Simplify mathematical expressions using stack-based state management, handling variables, operators, and polynomial term…

第K个语法符号

Determine the K-th symbol in a recursively generated grammar table using math and bit manipulation patterns efficiently.

所有可能的真二叉树

Generate all possible full binary trees with n nodes, focusing on dynamic programming and binary tree traversal.

解析布尔表达式

Solve the "Parsing A Boolean Expression" problem by evaluating boolean expressions using stack-based state management, r…

找出第 N 个二进制字符串中的第 K 位

Determine the k-th bit in the n-th binary string using a recursive construction that inverts and reverses previous strin…

好因子的最大数目

Solve Maximize Number of Nice Divisors by splitting primeFactors into mostly 3s and using fast modular exponentiation.

找出游戏的获胜者

Find the winner of a circular game by simulating the elimination process with a queue-driven approach.

统计好数字的数目

Count Good Numbers uses a mathematical pattern with recursion to efficiently count digit strings of length n under stric…

数组元素的最小非零乘积

The problem asks to minimize the product of an array after performing bit-swapping operations on its binary representati…

从链表中移除节点

This problem requires removing nodes from a linked list when a larger node exists to their right, testing pointer manipu…

猴子碰撞的方法数

Calculate the total number of monkey collisions on a convex polygon using math and recursion efficiently for large n.

找出第 K 个字符 I

Find the K-th character in a progressively built string using math and bit manipulation efficiently.

找出第 K 个字符 II

Find the K-th character in a string game using bit manipulation and recursion, optimizing performance for large k values…

不同三位偶数的数目

Given an array of digits, find how many distinct 3-digit even numbers can be formed without repetition of digits and no …

等积子集的划分方案

Determine if you can partition an array into two subsets with equal product using recursion and bit manipulation.