枚举

计数质数

Count all prime numbers less than a given integer n using efficient array and math-based enumeration techniques.

最大回文数乘积

Find the largest palindromic number from the product of two n-digit integers using math and enumeration efficiently.

模糊坐标

Find all valid 2D coordinate possibilities for an ambiguous input string using backtracking and pruning techniques.

连续整数求和

Find the number of ways to express a number as the sum of consecutive positive integers.

数组中的最长山脉

Find the length of the longest subarray forming a mountain pattern using state transitions and two-pointer logic efficie…

重新排序得到 2 的幂

Determine if a number's digits can be rearranged to form a power of two using counting and hash-based checks.

超级回文数

Count all super-palindromes in a given numeric range, where each is a palindrome and square of a palindrome.

给定数字能组成的最大时间

Given four digits, determine the latest valid 24-hour time possible using each digit exactly once with backtracking.

强整数

Find all integers that can be expressed as x^i + y^j up to a given bound using a Hash Table plus Math approach.

顺次数

Find all integers within a range whose digits form a strictly increasing consecutive sequence using enumeration techniqu…

统计好三元组

Count Good Triplets requires identifying all triplets in an array that satisfy multiple absolute difference constraints …

重复至少 K 次且长度为 M 的模式

Determine if a subarray of length m repeats k or more consecutive times in a given integer array efficiently.

最多可达成的换楼请求数目

Find the maximum number of achievable transfer requests between buildings with constraints on net employee transfers.

统计子树中城市之间最大距离

This problem asks you to count subtrees in a tree structure where the maximum distance between any two cities matches sp…

网络信号最好的坐标

Determine the coordinate with the maximum network quality by summing signal strengths from all reachable towers efficien…

执行操作后字典序最小的字符串

Optimize a string through rotations and additions to get the lexicographically smallest possible result using string man…

统计只差一个字符的子串数目

Count all substrings from s that differ by exactly one character from some substring in t using precise substring compar…

一个图中连通三元组的最小度数

Find the minimum degree of a connected trio in a graph using enumeration over nodes and edges.

将字符串拆分为递减的连续值

Check if a string of digits can be split into descending consecutive values where the difference between them is 1.

找出所有子集的异或总和再求和

Compute the sum of all subset XOR totals using a backtracking search with pruning for arrays of small size.

统计平方和三元组的数目

Count Square Sum Triples asks to find the number of integer triples where a² + b² = c² for values between 1 and n.

三除数

Determine if a given integer has exactly three positive divisors.

检查操作是否合法

Determine if a move on an 8x8 board is legal by validating lines in all directions using array and matrix patterns.

统计特殊四元组

Count Special Quadruplets requires scanning arrays and using hash lookups to efficiently find quadruplets matching sum c…