--- title: 2.05 ✅ Stack type: docs weight: 5 --- # Stack  - 括号匹配问题及类似问题。第 20 题,第 921 题,第 1021 题。 - 栈的基本 pop 和 push 操作。第 71 题,第 150 题,第 155 题,第 224 题,第 225 题,第 232 题,第 946 题,第 1047 题。 - 利用栈进行编码问题。第 394 题,第 682 题,第 856 题,第 880 题。 - **单调栈**。**利用栈维护一个单调递增或者递减的下标数组**。第 84 题,第 456 题,第 496 题,第 503 题,第 739 题,第 901 题,第 907 题,第 1019 题。 | No. | Title | Solution | Difficulty | TimeComplexity | SpaceComplexity |Favorite| Acceptance | |:--------:|:------- | :--------: | :----------: | :----: | :-----: | :-----: |:-----: | |0020|Valid Parentheses|[Go]({{< relref "/ChapterFour/0001~0099/0020.Valid-Parentheses.md" >}})|Easy| O(log n)| O(1)||40.0%| |0042|Trapping Rain Water|[Go]({{< relref "/ChapterFour/0001~0099/0042.Trapping-Rain-Water.md" >}})|Hard| O(n)| O(1)|❤️|51.5%| |0071|Simplify Path|[Go]({{< relref "/ChapterFour/0001~0099/0071.Simplify-Path.md" >}})|Medium| O(n)| O(n)|❤️|34.9%| |0084|Largest Rectangle in Histogram|[Go]({{< relref "/ChapterFour/0001~0099/0084.Largest-Rectangle-in-Histogram.md" >}})|Hard| O(n)| O(n)|❤️|37.4%| |0094|Binary Tree Inorder Traversal|[Go]({{< relref "/ChapterFour/0001~0099/0094.Binary-Tree-Inorder-Traversal.md" >}})|Medium| O(n)| O(1)||66.2%| |0103|Binary Tree Zigzag Level Order Traversal|[Go]({{< relref "/ChapterFour/0100~0199/0103.Binary-Tree-Zigzag-Level-Order-Traversal.md" >}})|Medium| O(n)| O(n)||50.4%| |0144|Binary Tree Preorder Traversal|[Go]({{< relref "/ChapterFour/0100~0199/0144.Binary-Tree-Preorder-Traversal.md" >}})|Medium| O(n)| O(1)||57.8%| |0145|Binary Tree Postorder Traversal|[Go]({{< relref "/ChapterFour/0100~0199/0145.Binary-Tree-Postorder-Traversal.md" >}})|Medium| O(n)| O(1)||58.0%| |0150|Evaluate Reverse Polish Notation|[Go]({{< relref "/ChapterFour/0100~0199/0150.Evaluate-Reverse-Polish-Notation.md" >}})|Medium| O(n)| O(1)||38.2%| |0155|Min Stack|[Go]({{< relref "/ChapterFour/0100~0199/0155.Min-Stack.md" >}})|Easy| O(n)| O(n)||46.7%| |0173|Binary Search Tree Iterator|[Go]({{< relref "/ChapterFour/0100~0199/0173.Binary-Search-Tree-Iterator.md" >}})|Medium| O(n)| O(1)||60.5%| |0224|Basic Calculator|[Go]({{< relref "/ChapterFour/0200~0299/0224.Basic-Calculator.md" >}})|Hard| O(n)| O(n)||38.2%| |0225|Implement Stack using Queues|[Go]({{< relref "/ChapterFour/0200~0299/0225.Implement-Stack-using-Queues.md" >}})|Easy| O(n)| O(n)||47.8%| |0227|Basic Calculator II|[Go]({{< relref "/ChapterFour/0200~0299/0227.Basic-Calculator-II.md" >}})|Medium||||38.7%| |0232|Implement Queue using Stacks|[Go]({{< relref "/ChapterFour/0200~0299/0232.Implement-Queue-using-Stacks.md" >}})|Easy| O(n)| O(n)||52.6%| |0331|Verify Preorder Serialization of a Binary Tree|[Go]({{< relref "/ChapterFour/0300~0399/0331.Verify-Preorder-Serialization-of-a-Binary-Tree.md" >}})|Medium| O(n)| O(1)||41.1%| |0341|Flatten Nested List Iterator|[Go]({{< relref "/ChapterFour/0300~0399/0341.Flatten-Nested-List-Iterator.md" >}})|Medium||||54.8%| |0385|Mini Parser|[Go]({{< relref "/ChapterFour/0300~0399/0385.Mini-Parser.md" >}})|Medium||||34.6%| |0394|Decode String|[Go]({{< relref "/ChapterFour/0300~0399/0394.Decode-String.md" >}})|Medium| O(n)| O(n)||52.9%| |0402|Remove K Digits|[Go]({{< relref "/ChapterFour/0400~0499/0402.Remove-K-Digits.md" >}})|Medium| O(n)| O(1)||28.7%| |0456|132 Pattern|[Go]({{< relref "/ChapterFour/0400~0499/0456.132-Pattern.md" >}})|Medium| O(n)| O(n)||30.7%| |0496|Next Greater Element I|[Go]({{< relref "/ChapterFour/0400~0499/0496.Next-Greater-Element-I.md" >}})|Easy| O(n)| O(n)||65.8%| |0503|Next Greater Element II|[Go]({{< relref "/ChapterFour/0500~0599/0503.Next-Greater-Element-II.md" >}})|Medium| O(n)| O(n)||58.7%| |0636|Exclusive Time of Functions|[Go]({{< relref "/ChapterFour/0600~0699/0636.Exclusive-Time-of-Functions.md" >}})|Medium| O(n)| O(n)||54.9%| |0682|Baseball Game|[Go]({{< relref "/ChapterFour/0600~0699/0682.Baseball-Game.md" >}})|Easy| O(n)| O(n)||67.3%| |0726|Number of Atoms|[Go]({{< relref "/ChapterFour/0700~0799/0726.Number-of-Atoms.md" >}})|Hard| O(n)| O(n) |❤️|51.0%| |0735|Asteroid Collision|[Go]({{< relref "/ChapterFour/0700~0799/0735.Asteroid-Collision.md" >}})|Medium| O(n)| O(n) ||43.3%| |0739|Daily Temperatures|[Go]({{< relref "/ChapterFour/0700~0799/0739.Daily-Temperatures.md" >}})|Medium| O(n)| O(n) ||64.8%| |0844|Backspace String Compare|[Go]({{< relref "/ChapterFour/0800~0899/0844.Backspace-String-Compare.md" >}})|Easy| O(n)| O(n) ||47.1%| |0856|Score of Parentheses|[Go]({{< relref "/ChapterFour/0800~0899/0856.Score-of-Parentheses.md" >}})|Medium| O(n)| O(n)||64.8%| |0880|Decoded String at Index|[Go]({{< relref "/ChapterFour/0800~0899/0880.Decoded-String-at-Index.md" >}})|Medium| O(n)| O(n)||28.2%| |0895|Maximum Frequency Stack|[Go]({{< relref "/ChapterFour/0800~0899/0895.Maximum-Frequency-Stack.md" >}})|Hard| O(n)| O(n) ||63.2%| |0901|Online Stock Span|[Go]({{< relref "/ChapterFour/0900~0999/0901.Online-Stock-Span.md" >}})|Medium| O(n)| O(n) ||61.4%| |0907|Sum of Subarray Minimums|[Go]({{< relref "/ChapterFour/0900~0999/0907.Sum-of-Subarray-Minimums.md" >}})|Medium| O(n)| O(n)|❤️|33.1%| |0921|Minimum Add to Make Parentheses Valid|[Go]({{< relref "/ChapterFour/0900~0999/0921.Minimum-Add-to-Make-Parentheses-Valid.md" >}})|Medium| O(n)| O(n)||74.9%| |0946|Validate Stack Sequences|[Go]({{< relref "/ChapterFour/0900~0999/0946.Validate-Stack-Sequences.md" >}})|Medium| O(n)| O(n)||64.4%| |1003|Check If Word Is Valid After Substitutions|[Go]({{< relref "/ChapterFour/1000~1099/1003.Check-If-Word-Is-Valid-After-Substitutions.md" >}})|Medium| O(n)| O(1)||56.7%| |1019|Next Greater Node In Linked List|[Go]({{< relref "/ChapterFour/1000~1099/1019.Next-Greater-Node-In-Linked-List.md" >}})|Medium| O(n)| O(1)||58.3%| |1021|Remove Outermost Parentheses|[Go]({{< relref "/ChapterFour/1000~1099/1021.Remove-Outermost-Parentheses.md" >}})|Easy| O(n)| O(1)||79.2%| |1047|Remove All Adjacent Duplicates In String|[Go]({{< relref "/ChapterFour/1000~1099/1047.Remove-All-Adjacent-Duplicates-In-String.md" >}})|Easy| O(n)| O(1)||71.1%| |1249|Minimum Remove to Make Valid Parentheses|[Go]({{< relref "/ChapterFour/1200~1299/1249.Minimum-Remove-to-Make-Valid-Parentheses.md" >}})|Medium||||64.2%| |1673|Find the Most Competitive Subsequence|[Go]({{< relref "/ChapterFour/1600~1699/1673.Find-the-Most-Competitive-Subsequence.md" >}})|Medium||||45.5%| |------------|-------------------------------------------------------|-------| ----------------| ---------------|-------------|-------------|-------------| ----------------------------------------------