数论

计数质数

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

各位相加

Add Digits involves repeatedly summing digits of a number until a single digit is obtained.

镜面反射

Given a square room with mirrors, find which receptor a laser ray will hit first based on two integers, p and q.

回文质数

The Prime Palindrome problem asks for the smallest prime palindrome greater than or equal to a given integer.

卡牌分组

Solve the problem of determining if a deck can be partitioned into groups with equal occurrences of card values.

按公因数计算最大组件大小

Find the largest connected component in an array where edges exist between numbers sharing a common factor greater than …

丑数 III

Find the nth positive integer divisible by a, b, or c using binary search over the answer space efficiently and accurate…

检查「好数组」

Determine if a given array of positive integers can generate 1 using integer multiples of any subset, leveraging number …

最简分数

Generate simplified fractions between 0 and 1 with denominators up to a given integer n.

n 的第 k 个因子

Find the kth factor of n by scanning divisors carefully or using factor pairs to skip unnecessary checks.

带阈值的图连通性

In 'Graph Connectivity With Threshold,' determine if cities are connected based on common divisors exceeding a threshold…

生成乘积数组的方案数

Determine the number of arrays of size n where the product equals k using prime factorization and combinatorial DP techn…

互质树

Determine the closest coprime ancestor for each node in a tree using efficient traversal and state tracking of node valu…

N 次操作后的最大分数和

Maximize the score after n operations by selecting pairs from the array and using their GCD with dynamic programming or …

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.

序列中不同最大公约数的数目

Given an array of positive integers, find the number of different subsequences' GCDs.

三除数

Determine if a given integer has exactly three positive divisors.

找出数组的最大公约数

Find the greatest common divisor of the smallest and largest numbers in an integer array.

好子集的数目

Find the number of good subsets in an integer array, where each subset's product is the product of distinct primes.

数组的最大公因数排序

The GCD Sort problem challenges you to sort an array using a specific gcd-based swap method.

可互换矩形的组数

Count all pairs of rectangles that share the exact width-to-height ratio using efficient array scanning and hash lookup.

统计可以被 K 整除的下标对数目

Count Array Pairs Divisible by K requires counting index pairs whose products are divisible by a given number k.

替换数组中的非互质数

Replace Non-Coprime Numbers in Array uses stack-based state management to iteratively merge adjacent non-coprime integer…

表示一个折线图的最少线段数

Determine the fewest lines needed to accurately connect stock price points in a line chart using array and math reasonin…