前缀和模式

除了自身以外数组的乘积

Solve the 'Product of Array Except Self' problem by calculating the product of all elements except self for each index e…

区域和检索 - 数组不可变

The Range Sum Query - Immutable problem involves implementing a data structure to handle range sum queries efficiently.

二维区域和检索 - 矩阵不可变

Design a 2D matrix class that efficiently handles sum queries with O(1) time complexity using a prefix sum approach.

寻找数组的中心下标

Find the pivot index in an array where the sums of elements on both sides are equal using array and prefix sum technique…

得分最高的最小轮调

Find the smallest rotation index with the highest score using array and prefix sum techniques.

航班预订统计

Solve Corporate Flight Bookings by marking range changes once, then building final seat totals with a single prefix sum …

子数组异或查询

Compute XOR results for multiple subarray queries using efficient prefix XOR to reduce repeated computation overhead in …

每个元音包含偶数次的最长子字符串

Find the longest substring with even counts of vowels using bitmasking and hash tables.

逐步求和得到正数的最小值

Find the minimum starting value to ensure the step-by-step sum of an array is always at least 1.

分割字符串的最大得分

Find the optimal split point in a binary string to maximize zeros on the left and ones on the right efficiently.

一维数组的动态和

Calculate the running sum of a given 1D array by updating each element to the sum of itself and all previous elements.

生成平衡数组的方案数

Solve Ways to Make a Fair Array by tracking parity sums before and after each removal with prefix-sum style accounting.

找到最高海拔

Find the highest altitude after a series of altitude changes during a road trip using prefix sum technique.

满足三条件之一需改变的最少字符数

This problem asks for the minimum operations to change two strings so that one of three conditions is met.

你能在你最喜欢的那天吃到你最喜欢的糖果吗？

Determine if you can eat a candy of your favorite type on a specific day, given daily limits and candy availability.

每个查询的最大异或值

Find the maximum XOR for each query based on a sorted array and bit manipulation.

人口最多的年份

Find the earliest year with the highest population using an array plus counting approach.

最美子字符串的数目

Count the number of wonderful non-empty substrings of a given string based on frequency conditions of characters.

长度为 3 的不同回文子序列

Count all unique length-3 palindromic subsequences in a string efficiently using hash tables and character positions.

找到数组的中间位置

Find the smallest middle index where the sum of elements on the left equals the sum on the right using prefix sums effic…

统计隐藏数组数目

Given a sequence of differences, count how many hidden sequences fit within a range using an array and prefix sum approa…

最小平均差

Find the index with the minimum average difference in an array using prefix sums.

分割数组的方案数

Count all valid ways to split a 0-indexed integer array into two non-empty parts using array plus prefix sum logic effic…

二的幂数组中查询范围内的乘积

The Range Product Queries of Powers problem requires calculating the product of powers of 2 for a range of queries on a …