638. Shopping Offers
- By
Wayne
We can use backtracking to find all the purchase combinations, and then take the lowest price.
39. Combination Sum
- By
This problem asks us to list all possible combinations, so we can use backtracking to find them. However, we must avoid finding duplicated combinations.
22. Generate Parentheses
- By
This problem asks us to list all possible combinations of parentheses, so we can use backtracking to solve it.
17. Letter Combinations of a Phone Number
- By
This problem asks us to list all possible strings, so we can think of using backtracking to solve it.
1673. Find the Most Competitive Subsequence
- By
We must first understand what the competitive subsequence in the problem is. When a is more competitive than b, this means that the letters of a are smaller than the letters of b at the same position.
503. Next Greater Element II
- By
This problem requires us to find the next greater number of each number in nums. We can use decreasing monotonic stack to solve it.
211. Design Add and Search Words Data Structure
- By
This problem asks us to build a word dictionary, which is obviously to use Trie. But it also asks to support dots ‘.’ where dots can match any letter.
208. Implement Trie (Prefix Tree)
- By
This problem is asking us to implement a very basic Trie.
117. Populating Next Right Pointers in Each Node II
- By
This problem requires us to point the next of the left node in each layer to the right node. Because it is processed layer by layer, it is very intuitive to think of using BFS to solve it.
116. Populating Next Right Pointers in Each Node
- By
This problem requires us to point the next of the left node in each layer to the right node. Because it is processed layer by layer, it is very intuitive to think of using BFS to solve it.
