From 5c25a2e85633a0b15d5dda1500b9e684a856925c Mon Sep 17 00:00:00 2001 From: nite Date: Mon, 22 Jun 2026 20:50:10 +1000 Subject: [PATCH] u --- AGENTS.md | 2 + top-100-liked/41/leetcode_test.go | 35 ++++++++++++++++ top-100-liked/42/leetcode_test.go | 27 +++++++++++++ top-100-liked/43/leetcode_test.go | 66 +++++++++++++++++++++++++++++++ top-100-liked/44/leetcode_test.go | 30 ++++++++++++++ top-100-liked/45/leetcode_test.go | 33 ++++++++++++++++ top-100-liked/46/leetcode_test.go | 25 ++++++++++++ 7 files changed, 218 insertions(+) create mode 100644 AGENTS.md create mode 100644 top-100-liked/41/leetcode_test.go create mode 100644 top-100-liked/42/leetcode_test.go create mode 100644 top-100-liked/43/leetcode_test.go create mode 100644 top-100-liked/44/leetcode_test.go create mode 100644 top-100-liked/45/leetcode_test.go create mode 100644 top-100-liked/46/leetcode_test.go diff --git a/AGENTS.md b/AGENTS.md new file mode 100644 index 0000000..98c91c2 --- /dev/null +++ b/AGENTS.md @@ -0,0 +1,2 @@ +这是 leetcode 题练习 repo。 +第一层目录为题集名称，第二层目录为题号。 diff --git a/top-100-liked/41/leetcode_test.go b/top-100-liked/41/leetcode_test.go new file mode 100644 index 0000000..f73a80e --- /dev/null +++ b/top-100-liked/41/leetcode_test.go @@ -0,0 +1,35 @@ +package top100liked + +// https://leetcode.cn/problems/binary-tree-level-order-traversal/?envType=study-plan-v2&envId=top-100-liked + +type TreeNode struct { + Val int + Left *TreeNode + Right *TreeNode +} + +func levelOrder(root *TreeNode) [][]int { + if root == nil { + return [][]int{} + } + + queue := []*TreeNode{root} + res := [][]int{} + for len(queue) > 0 { + currentLayerRes := []int{} + tmpQueue := []*TreeNode{} + for i := range queue { + currentNode := queue[i] + currentLayerRes = append(currentLayerRes, currentNode.Val) + if currentNode.Left != nil { + tmpQueue = append(tmpQueue, currentNode.Left) + } + if currentNode.Right != nil { + tmpQueue = append(tmpQueue, currentNode.Right) + } + } + queue = tmpQueue + res = append(res, currentLayerRes) + } + return res +} diff --git a/top-100-liked/42/leetcode_test.go b/top-100-liked/42/leetcode_test.go new file mode 100644 index 0000000..4f4c527 --- /dev/null +++ b/top-100-liked/42/leetcode_test.go @@ -0,0 +1,27 @@ +package top100liked + +// https://leetcode.cn/problems/convert-sorted-array-to-binary-search-tree/description/?envType=study-plan-v2&envId=top-100-liked + +type TreeNode struct { + Val int + Left *TreeNode + Right *TreeNode +} + +func sortedArrayToBST(nums []int) *TreeNode { + if len(nums) == 0 { + return nil + } + if len(nums) == 1 { + return &TreeNode{Val: nums[0]} + } + if len(nums) == 2 { + return &TreeNode{Val: nums[1], Left: &TreeNode{Val: nums[0]}} + } + rootIdx := len(nums) / 2 + rootVal := nums[rootIdx] + root := &TreeNode{Val: rootVal} + root.Left = sortedArrayToBST(nums[:rootIdx]) + root.Right = sortedArrayToBST(nums[rootIdx+1:]) + return root +} diff --git a/top-100-liked/43/leetcode_test.go b/top-100-liked/43/leetcode_test.go new file mode 100644 index 0000000..2985e37 --- /dev/null +++ b/top-100-liked/43/leetcode_test.go @@ -0,0 +1,66 @@ +package top100liked + +// https://leetcode.cn/problems/validate-binary-search-tree/description/?envType=study-plan-v2&envId=top-100-liked + +type TreeNode struct { + Val int + Left *TreeNode + Right *TreeNode +} + +// AC, 但很慢 +// func inorderTraversal(root *TreeNode) []int { +// if root == nil { +// return []int{} +// } +// res := []int{} +// if root.Left != nil { +// res = append(res, inorderTraversal(root.Left)...) +// } +// res = append(res, root.Val) +// if root.Right != nil { +// res = append(res, inorderTraversal(root.Right)...) +// } +// return res +// } + +// func isValidBST(root *TreeNode) bool { +// if root == nil { +// return true +// } +// l := inorderTraversal(root) +// if len(l) == 1 { +// return true +// } +// for i, j := 0, 1; j < len(l); { +// if l[i] >= l[j] { +// return false +// } + +// i++ +// j++ +// } +// return true +// } + +func isValidBST(root *TreeNode) bool { + var prev *int + var inorder func(node *TreeNode) bool + inorder = func(node *TreeNode) bool { + if node == nil { + return true + } + if !inorder(node.Left) { + return false + } + if prev != nil && *prev >= node.Val { + return false + } + prev = &node.Val + if !inorder(node.Right) { + return false + } + return true + } + return inorder(root) +} diff --git a/top-100-liked/44/leetcode_test.go b/top-100-liked/44/leetcode_test.go new file mode 100644 index 0000000..437c668 --- /dev/null +++ b/top-100-liked/44/leetcode_test.go @@ -0,0 +1,30 @@ +package top100liked + +// https://leetcode.cn/problems/kth-smallest-element-in-a-bst/description/?envType=study-plan-v2&envId=top-100-liked + +type TreeNode struct { + Val int + Left *TreeNode + Right *TreeNode +} + +func kthSmallest(root *TreeNode, k int) int { + res, cnt := 0, 0 + var helper func(node *TreeNode) bool + helper = func(node *TreeNode) bool { + if node == nil { + return false + } + if helper(node.Left) { + return true + } + cnt++ + if cnt == k { + res = node.Val + return true + } + return helper(node.Right) + } + helper(root) + return res +} diff --git a/top-100-liked/45/leetcode_test.go b/top-100-liked/45/leetcode_test.go new file mode 100644 index 0000000..2891104 --- /dev/null +++ b/top-100-liked/45/leetcode_test.go @@ -0,0 +1,33 @@ +package top100liked + +// https://leetcode.cn/problems/binary-tree-right-side-view/description/?envType=study-plan-v2&envId=top-100-liked + +type TreeNode struct { + Val int + Left *TreeNode + Right *TreeNode +} + +func rightSideView(root *TreeNode) []int { + if root == nil { + return []int{} + } + queue := []*TreeNode{root} + res := []int{} + for len(queue) > 0 { + tmpQueue := []*TreeNode{} + for i := range queue { + if i == len(queue)-1 { + res = append(res, queue[i].Val) + } + if queue[i].Left != nil { + tmpQueue = append(tmpQueue, queue[i].Left) + } + if queue[i].Right != nil { + tmpQueue = append(tmpQueue, queue[i].Right) + } + } + queue = tmpQueue + } + return res +} diff --git a/top-100-liked/46/leetcode_test.go b/top-100-liked/46/leetcode_test.go new file mode 100644 index 0000000..aae1d5c --- /dev/null +++ b/top-100-liked/46/leetcode_test.go @@ -0,0 +1,25 @@ +package top100liked + +// https://leetcode.cn/problems/flatten-binary-tree-to-linked-list/description/?envType=study-plan-v2&envId=top-100-liked + +type TreeNode struct { + Val int + Left *TreeNode + Right *TreeNode +} + +func flatten(root *TreeNode) { + var prev *TreeNode + var helper func(*TreeNode) + helper = func(node *TreeNode) { + if node == nil { + return + } + helper(node.Right) + helper(node.Left) + node.Right = prev + node.Left = nil + prev = node + } + helper(root) +}