数学·结合·enumeration 模式

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.

连续整数求和

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

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.

k 镜像数字的和

This problem requires finding the sum of the n smallest k-mirror numbers by generating palindromes in base-k and base-10…

设置时间的最少代价

Calculate the minimum fatigue to set a microwave cooking time using digit moves and pushes efficiently.

买钢笔和铅笔的方案数

Calculate all distinct ways to spend a fixed total on pens and pencils using a straightforward enumeration strategy.

公因子的数目

The problem asks to find the number of common factors of two positive integers a and b.

反转之后的数字和

Determine if a non-negative integer can be expressed as the sum of a number and its reverse using enumeration and math r…

统计对称整数的数目

Count Symmetric Integers finds numbers where the sum of the first half of digits equals the sum of the second half withi…

捕获黑皇后需要的最少移动次数

Determine the fewest moves to capture the black queen using only white pieces with careful position analysis.

最小可整除数位乘积 I

Find the smallest number greater than or equal to n whose digit product is divisible by t.