Merge pull request #1 from greyireland/master

merge  algorithm-pattern master

Author: pudgelee

README.md

@@ -18,28 +18,28 @@
 
 ### 入门篇 🐶
 
-- [go 语言入门](https://github.com/greyireland/algorithm-pattern/blob/master/introduction/golang.md)
-- [算法快速入门](https://github.com/greyireland/algorithm-pattern/blob/master/introduction/quickstart.md)
+- [go 语言入门](./introduction/golang.md)
+- [算法快速入门](./introduction/quickstart.md)
 
 ### 数据结构篇 🐰
 
-- [二叉树](https://github.com/greyireland/algorithm-pattern/blob/master/data_structure/binary_tree.md)
-- [链表](https://github.com/greyireland/algorithm-pattern/blob/master/data_structure/linked_list.md)
-- [栈和队列](https://github.com/greyireland/algorithm-pattern/blob/master/data_structure/stack_queue.md)
-- [二进制](https://github.com/greyireland/algorithm-pattern/blob/master/data_structure/binary_op.md)
+- [二叉树](./data_structure/binary_tree.md)
+- [链表](./data_structure/linked_list.md)
+- [栈和队列](./data_structure/stack_queue.md)
+- [二进制](./data_structure/binary_op.md)
 
 ### 基础算法篇 🐮
 
-- [二分搜索](https://github.com/greyireland/algorithm-pattern/blob/master/basic_algorithm/binary_search.md)
-- [排序算法](https://github.com/greyireland/algorithm-pattern/blob/master/basic_algorithm/sort.md)
-- [动态规划](https://github.com/greyireland/algorithm-pattern/blob/master/basic_algorithm/dp.md)
+- [二分搜索](./basic_algorithm/binary_search.md)
+- [排序算法](./basic_algorithm/sort.md)
+- [动态规划](./basic_algorithm/dp.md)
 
 ### 算法思维 🦁
 
-- [递归思维](https://github.com/greyireland/algorithm-pattern/blob/master/advanced_algorithm/recursion.md)
-- [滑动窗口思想](https://github.com/greyireland/algorithm-pattern/blob/master/advanced_algorithm/slide_window.md)
-- [二叉搜索树](https://github.com/greyireland/algorithm-pattern/blob/master/advanced_algorithm/binary_search_tree.md)
-- [回溯法](https://github.com/greyireland/algorithm-pattern/blob/master/advanced_algorithm/backtrack.md)
+- [递归思维](./advanced_algorithm/recursion.md)
+- [滑动窗口思想](./advanced_algorithm/slide_window.md)
+- [二叉搜索树](./advanced_algorithm/binary_search_tree.md)
+- [回溯法](./advanced_algorithm/backtrack.md)
 
 ## 心得体会
 
@@ -85,8 +85,19 @@
 
 [我看过的 100 本书](https://github.com/greyireland/awesome-programming-books-1)
 
-## 后续
+## 更新计划
 
 持续更新中，觉得还可以的话点个 **star** 收藏呀 ⭐️~
 
 【 Github 】[https://github.com/greyireland/algorithm-pattern](https://github.com/greyireland/algorithm-pattern) ⭐️
+
+## 完成打卡
+
+完成计划之后，可以提交 Pull requests，在下面添加自己的项目仓库，完成自己的算法模板打卡呀~
+
+| 完成 | 用户                                              | 项目地址                                                            |
+| ---- | ------------------------------------------------- | ------------------------------------------------------------------- |
+| ✅   | [easyui](https://github.com/easyui/) | [algorithm-pattern-swift(Swift 实现)](https://github.com/easyui/algorithm-pattern-swift),[在线文档 Gitbook](https://zyj.gitbook.io/algorithm-pattern-swift/) |
+| ✅   | [wardseptember](https://github.com/wardseptember) | [notes(Java 实现)](https://github.com/wardseptember/notes)          |
+| ✅   | [dashidhy](https://github.com/dashidhy) | [algorithm-pattern-python(Python 实现)](https://github.com/dashidhy/algorithm-pattern-python) |
+| ✅   | [binzi56](https://github.com/binzi56) | [algorithm-pattern-c(c++ 实现)](https://github.com/binzi56/algorithm-pattern-c) |

basic_algorithm/dp.md

@@ -356,6 +356,7 @@ func canJump(nums []int) bool {
 > 你的目标是使用最少的跳跃次数到达数组的最后一个位置。
 
 ```go
+// v1动态规划（其他语言超时参考v2）
 func jump(nums []int) int {
     // 状态：f[i] 表示从起点到当前位置最小次数
     // 推导：f[i] = f[j],a[j]+j >=i,min(f[j]+1)
@@ -383,6 +384,26 @@ func min(a, b int) int {
 }
 ```
 
+```go
+// v2 动态规划+贪心优化
+func jump(nums []int) int {
+    n:=len(nums)
+    f := make([]int, n)
+    f[0] = 0
+    for i := 1; i < n; i++ {
+        // 取第一个能跳到当前位置的点即可
+        // 因为跳跃次数的结果集是单调递增的，所以贪心思路是正确的
+        idx:=0
+        for idx<n&&idx+nums[idx]<i{
+            idx++
+        }
+        f[i]=f[idx]+1
+    }
+    return f[n-1]
+}
+
+```
+
 ### [palindrome-partitioning-ii](https://leetcode-cn.com/problems/palindrome-partitioning-ii/)
 
 > 给定一个字符串 _s_，将 _s_ 分割成一些子串，使每个子串都是回文串。
@@ -486,32 +507,37 @@ func wordBreak(s string, wordDict []string) bool {
 	}
 	f := make([]bool, len(s)+1)
 	f[0] = true
-	max := maxLen(wordDict)
+	max,dict := maxLen(wordDict)
 	for i := 1; i <= len(s); i++ {
-		for j := i - max; j < i && j >= 0; j++ {
-			if f[j] && inDict(s[j:i]) {
+		l := 0
+		if i - max > 0 {
+			l = i - max
+		}
+		for j := l; j < i; j++ {
+			if f[j] && inDict(s[j:i],dict) {
 				f[i] = true
-				break
+                break
 			}
 		}
 	}
 	return f[len(s)]
 }
 
-var dict = make(map[string]bool)
 
-func maxLen(wordDict []string) int {
+
+func maxLen(wordDict []string) (int,map[string]bool) {
+    dict := make(map[string]bool)
 	max := 0
 	for _, v := range wordDict {
 		dict[v] = true
 		if len(v) > max {
 			max = len(v)
 		}
 	}
-	return max
+	return max,dict
 }
 
-func inDict(s string) bool {
+func inDict(s string,dict map[string]bool) bool {
 	_, ok := dict[s]
 	return ok
 }

data_structure/binary_tree.md

@@ -640,9 +640,7 @@ func zigzagLevelOrder(root *TreeNode) [][]int {
 }
 func reverse(nums []int) {
 	for i := 0; i < len(nums)/2; i++ {
-		t := nums[i]
-		nums[i] = nums[len(nums)-1-i]
-		nums[len(nums)-1-i] = t
+		nums[i], nums[len(nums)-1-i] = nums[len(nums)-1-i], nums[i]
 	}
 }
 ```

data_structure/linked_list.md

@@ -379,7 +379,8 @@ func hasCycle(head *ListNode) bool {
     fast := head.Next
     slow := head
     for fast != nil && fast.Next != nil {
-        if fast.Val == slow.Val {
+        // 比较指针是否相等（不要使用val比较！）
+        if fast == slow {
             return true
         }
         fast = fast.Next.Next
@@ -389,7 +390,7 @@ func hasCycle(head *ListNode) bool {
 }
 ```
 
-### [linked-list-cycle-ii](https://leetcode-cn.com/problems/https://leetcode-cn.com/problems/linked-list-cycle-ii/)
+### [linked-list-cycle-ii](https://leetcode-cn.com/problems/linked-list-cycle-ii/)
 
 > 给定一个链表，返回链表开始入环的第一个节点。  如果链表无环，则返回  `null`。
 
@@ -581,6 +582,6 @@ func copyRandomList(head *Node) *Node {
 - [ ] [sort-list](https://leetcode-cn.com/problems/sort-list/)
 - [ ] [reorder-list](https://leetcode-cn.com/problems/reorder-list/)
 - [ ] [linked-list-cycle](https://leetcode-cn.com/problems/linked-list-cycle/)
-- [ ] [linked-list-cycle-ii](https://leetcode-cn.com/problems/https://leetcode-cn.com/problems/linked-list-cycle-ii/)
+- [ ] [linked-list-cycle-ii](https://leetcode-cn.com/problems/linked-list-cycle-ii/)
 - [ ] [palindrome-linked-list](https://leetcode-cn.com/problems/palindrome-linked-list/)
 - [ ] [copy-list-with-random-pointer](https://leetcode-cn.com/problems/copy-list-with-random-pointer/)

data_structure/stack_queue.md

@@ -83,8 +83,9 @@ func (this *MinStack) GetMin() int {
 
 [evaluate-reverse-polish-notation](https://leetcode-cn.com/problems/evaluate-reverse-polish-notation/)
 
-> **波兰表达式计算** > **输入:** ["2", "1", "+", "3", "*"] > **输出:** 9
-> **解释:** ((2 + 1) \* 3) = 9
+> **波兰表达式计算** > **输入:** `["2", "1", "+", "3", "*"]` > **输出:** 9
+>
+> **解释:** `((2 + 1) * 3) = 9`
 
 思路：通过栈保存原来的元素，遇到表达式弹出运算，再推入结果，重复这个过程
 
@@ -100,7 +101,7 @@ func evalRPN(tokens []string) int {
             if len(stack)<2{
                 return -1
             }
-            // 注意：a为除数，b为被除数
+            // 注意：a为被除数，b为除数
             b:=stack[len(stack)-1]
             a:=stack[len(stack)-2]
             stack=stack[:len(stack)-2]
@@ -513,7 +514,7 @@ func updateMatrix(matrix [][]int) [][]int {
 ## 总结
 
 - 熟悉栈的使用场景
-  - 后出先出，保存临时值
+  - 后入先出，保存临时值
   - 利用栈 DFS 深度搜索
 - 熟悉队列的使用场景
   - 利用队列 BFS 广度搜索