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📖 Content of this article: leetcode weekly The 278th game of the week is really difficult, but you can still brush simple sorting + traversal double pointer + prefix and sum 📑 Article column: leetcode weekly game punch in 📆 Last updated: January 23, 2022 leetcode weekly Game 277 of the week 🙊 Personal profile: a Junior Program ape who ...

Next larger element 1 Title Link Maintain a monotonically decreasing stack, that is, when the traversal element is larger than the top element of the stack, save the result and pop up the top element of the stack In order to get the results in the order of subset array 1, we need to use hash table to establish mapping relationship when ...

Double pointer algorithm - Introduction to the algorithm Overview of double pointer algorithm The double pointer algorithm should be a special traversal algorithm, which not only uses a single pointer to traverse, but uses double pointers. Note that the pointer here does not refer to pointers such as int *ptr. The double pointer algorithm can ...

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Common questions about linked lists, such as: Get the last k element, get the element in the middle position, judge whether there is a ring in the linked list, judge the length of the ring, and problems related to the length and position. These problems can be solved through the flexible use of double pointers. Sword finger Offer 22 The ...

The sequential array searches for a value The basic idea of binary search is that the search interval must be orderly In this paper, all search is based on the closed interval. At this time, the condition in while should be written as l < = R If you search by the open interval (r=nums.size()), the condition in while should be written ...

catalogue Question 1: continuous subarrays and Question 2: continuous array Question 3: intersecting linked list Question 4: goals and objectives Question 5: weight of the last stone II Question 6: constructing rectangles Question 7: change II Question 8: complete square Question 9: different paths II Question 10: stone game Leetcod ...

q54 spiral matrix Title portal Problem solution Traverse each row and column layer by layer. The last element of each row or column is the beginning of the next column or row. Because the side length of the matrix in the topic is not necessarily equal, there will be one more row or column in the end, which can be handled separate ...

catalogue IndexTree AC automata IndexTree Tree array or Binary Indexed Tree (English: Binary Indexed Tree), also named Fenwick tree after its inventor. Its original intention is to solve the calculation problem of Cumulative Frequency in data compression. Now it is mostly used to efficiently calculate the prefix sum, interval sum of ...

preface: The vast majority of binary tree problems can be solved by recursion. Mastering the first, middle and last sequence traversal and sequence traversal of binary tree is the basis for quickly solving binary tree problems. catalogue preface: Maximum depth of binary tree Idea: code: Same tree Idea: code: Symmetric binary tree Ide ...