Merge branch 'doocs:main' into main

Author: Nothing-avil

images/starcharts.svg

@@ -236,6 +236,47 @@ public:
 };
 ```
 
+#### Go
+
+```go
+func openLock(deadends []string, target string) int {
+	dead := map[string]bool{}
+	for _, s := range deadends {
+		dead[s] = true
+	}
+	if dead["0000"] {
+		return -1
+	}
+	if target == "0000" {
+		return 0
+	}
+	q := []string{"0000"}
+	visited := map[string]bool{"0000": true}
+	step := 0
+	for len(q) > 0 {
+		step++
+		size := len(q)
+		for i := 0; i < size; i++ {
+			cur := q[0]
+			q = q[1:]
+			for j := 0; j < 4; j++ {
+				for k := -1; k <= 1; k += 2 {
+					next := cur[:j] + string((cur[j]-'0'+byte(k)+10)%10+'0') + cur[j+1:]
+					if next == target {
+						return step
+					}
+					if !dead[next] && !visited[next] {
+						q = append(q, next)
+						visited[next] = true
+					}
+				}
+			}
+		}
+	}
+	return -1
+}
+```
+
 <!-- tabs:end -->
 
 <!-- solution:end -->

lcof2/剑指 Offer II 109. 开密码锁/README.md

@@ -0,0 +1,36 @@
+func openLock(deadends []string, target string) int {
+	dead := map[string]bool{}
+	for _, s := range deadends {
+		dead[s] = true
+	}
+	if dead["0000"] {
+		return -1
+	}
+	if target == "0000" {
+		return 0
+	}
+	q := []string{"0000"}
+	visited := map[string]bool{"0000": true}
+	step := 0
+	for len(q) > 0 {
+		step++
+		size := len(q)
+		for i := 0; i < size; i++ {
+			cur := q[0]
+			q = q[1:]
+			for j := 0; j < 4; j++ {
+				for k := -1; k <= 1; k += 2 {
+					next := cur[:j] + string((cur[j]-'0'+byte(k)+10)%10+'0') + cur[j+1:]
+					if next == target {
+						return step
+					}
+					if !dead[next] && !visited[next] {
+						q = append(q, next)
+						visited[next] = true
+					}
+				}
+			}
+		}
+	}
+	return -1
+}

lcof2/剑指 Offer II 109. 开密码锁/Solution.go

@@ -287,6 +287,68 @@ public:
 };
 ```
 
+#### Go
+
+```go
+func alienOrder(words []string) string {
+	n := len(words)
+	if n == 0 {
+		return ""
+	}
+	if n == 1 {
+		return words[0]
+	}
+	inDegree := make(map[byte]int)
+	graph := make(map[byte][]byte)
+	for _, word := range words {
+		for i := 0; i < len(word); i++ {
+			inDegree[word[i]] = 0
+		}
+	}
+	for i := 0; i < n-1; i++ {
+		w1, w2 := words[i], words[i+1]
+		minLen := len(w1)
+		if len(w2) < minLen {
+			minLen = len(w2)
+		}
+		foundDifference := false
+		for j := 0; j < minLen; j++ {
+			if w1[j] != w2[j] {
+				inDegree[w2[j]]++
+				graph[w1[j]] = append(graph[w1[j]], w2[j])
+				foundDifference = true
+				break
+			}
+		}
+		if !foundDifference && len(w1) > len(w2) {
+			return ""
+		}
+	}
+	queue := make([]byte, 0)
+	for k := range inDegree {
+		if inDegree[k] == 0 {
+			queue = append(queue, k)
+		}
+	}
+	res := make([]byte, 0)
+	for len(queue) > 0 {
+		node := queue[0]
+		queue = queue[1:]
+		res = append(res, node)
+		for _, next := range graph[node] {
+			inDegree[next]--
+			if inDegree[next] == 0 {
+				queue = append(queue, next)
+			}
+		}
+	}
+	if len(res) != len(inDegree) {
+		return ""
+	}
+	return string(res)
+}
+```
+
 <!-- tabs:end -->
 
 <!-- solution:end -->

lcof2/剑指 Offer II 114. 外星文字典/README.md

@@ -0,0 +1,57 @@
+func alienOrder(words []string) string {
+	n := len(words)
+	if n == 0 {
+		return ""
+	}
+	if n == 1 {
+		return words[0]
+	}
+	inDegree := make(map[byte]int)
+	graph := make(map[byte][]byte)
+	for _, word := range words {
+		for i := 0; i < len(word); i++ {
+			inDegree[word[i]] = 0
+		}
+	}
+	for i := 0; i < n-1; i++ {
+		w1, w2 := words[i], words[i+1]
+		minLen := len(w1)
+		if len(w2) < minLen {
+			minLen = len(w2)
+		}
+		foundDifference := false
+		for j := 0; j < minLen; j++ {
+			if w1[j] != w2[j] {
+				inDegree[w2[j]]++
+				graph[w1[j]] = append(graph[w1[j]], w2[j])
+				foundDifference = true
+				break
+			}
+		}
+		if !foundDifference && len(w1) > len(w2) {
+			return ""
+		}
+	}
+	queue := make([]byte, 0)
+	for k := range inDegree {
+		if inDegree[k] == 0 {
+			queue = append(queue, k)
+		}
+	}
+	res := make([]byte, 0)
+	for len(queue) > 0 {
+		node := queue[0]
+		queue = queue[1:]
+		res = append(res, node)
+		for _, next := range graph[node] {
+			inDegree[next]--
+			if inDegree[next] == 0 {
+				queue = append(queue, next)
+			}
+		}
+	}
+	if len(res) != len(inDegree) {
+		return ""
+	}
+	return string(res)
+}

lcof2/剑指 Offer II 114. 外星文字典/Solution.go

@@ -68,7 +68,9 @@ Employee 表:
 
 <!-- solution:start -->
 
-### 方法一
+### 方法一：自连接 + 条件筛选
+
+我们可以通过自连接 `Employee` 表，找出员工的工资以及其经理的工资，然后筛选出工资比经理高的员工。
 
 <!-- tabs:start -->
 
@@ -79,44 +81,22 @@ import pandas as pd
 
 
 def find_employees(employee: pd.DataFrame) -> pd.DataFrame:
-    df = employee.merge(right=employee, how="left", left_on="managerId", right_on="id")
-    emp = df[df["salary_x"] > df["salary_y"]]["name_x"]
-
-    return pd.DataFrame({"Employee": emp})
-```
-
-#### MySQL
-
-```sql
-SELECT Name AS Employee
-FROM Employee AS Curr
-WHERE
-    Salary > (
-        SELECT Salary
-        FROM Employee
-        WHERE Id = Curr.ManagerId
-    );
+    merged = employee.merge(
+        employee, left_on="managerId", right_on="id", suffixes=("", "_manager")
+    )
+    result = merged[merged["salary"] > merged["salary_manager"]][["name"]]
+    result.columns = ["Employee"]
+    return result
 ```
 
-<!-- tabs:end -->
-
-<!-- solution:end -->
-
-<!-- solution:start -->
-
-### 方法二
-
-<!-- tabs:start -->
-
 #### MySQL
 
 ```sql
 # Write your MySQL query statement below
-SELECT
-    e1.name AS Employee
+SELECT e1.name Employee
 FROM
-    Employee AS e1
-    JOIN Employee AS e2 ON e1.managerId = e2.id
+    Employee e1
+    JOIN Employee e2 ON e1.managerId = e2.id
 WHERE e1.salary > e2.salary;
 ```
 

solution/0100-0199/0181.Employees Earning More Than Their Managers/README.md

@@ -68,7 +68,9 @@ Employee table:
 
 <!-- solution:start -->
 
-### Solution 1
+### Solution 1: Self-Join + Conditional Filtering
+
+We can find employees' salaries and their managers' salaries by self-joining the `Employee` table, then filter out employees whose salaries are higher than their managers' salaries.
 
 <!-- tabs:start -->
 
@@ -79,44 +81,22 @@ import pandas as pd
 
 
 def find_employees(employee: pd.DataFrame) -> pd.DataFrame:
-    df = employee.merge(right=employee, how="left", left_on="managerId", right_on="id")
-    emp = df[df["salary_x"] > df["salary_y"]]["name_x"]
-
-    return pd.DataFrame({"Employee": emp})
-```
-
-#### MySQL
-
-```sql
-SELECT Name AS Employee
-FROM Employee AS Curr
-WHERE
-    Salary > (
-        SELECT Salary
-        FROM Employee
-        WHERE Id = Curr.ManagerId
-    );
+    merged = employee.merge(
+        employee, left_on="managerId", right_on="id", suffixes=("", "_manager")
+    )
+    result = merged[merged["salary"] > merged["salary_manager"]][["name"]]
+    result.columns = ["Employee"]
+    return result
 ```
 
-<!-- tabs:end -->
-
-<!-- solution:end -->
-
-<!-- solution:start -->
-
-### Solution 2
-
-<!-- tabs:start -->
-
 #### MySQL
 
 ```sql
 # Write your MySQL query statement below
-SELECT
-    e1.name AS Employee
+SELECT e1.name Employee
 FROM
-    Employee AS e1
-    JOIN Employee AS e2 ON e1.managerId = e2.id
+    Employee e1
+    JOIN Employee e2 ON e1.managerId = e2.id
 WHERE e1.salary > e2.salary;
 ```
 

solution/0100-0199/0181.Employees Earning More Than Their Managers/README_EN.md

@@ -2,7 +2,9 @@
 
 
 def find_employees(employee: pd.DataFrame) -> pd.DataFrame:
-    df = employee.merge(right=employee, how="left", left_on="managerId", right_on="id")
-    emp = df[df["salary_x"] > df["salary_y"]]["name_x"]
-
-    return pd.DataFrame({"Employee": emp})
+    merged = employee.merge(
+        employee, left_on="managerId", right_on="id", suffixes=("", "_manager")
+    )
+    result = merged[merged["salary"] > merged["salary_manager"]][["name"]]
+    result.columns = ["Employee"]
+    return result

solution/0100-0199/0181.Employees Earning More Than Their Managers/Solution.py

@@ -1,8 +1,6 @@
-SELECT Name AS Employee
-FROM Employee AS Curr
-WHERE
-    Salary > (
-        SELECT Salary
-        FROM Employee
-        WHERE Id = Curr.ManagerId
-    );
+# Write your MySQL query statement below
+SELECT e1.name Employee
+FROM
+    Employee e1
+    JOIN Employee e2 ON e1.managerId = e2.id
+WHERE e1.salary > e2.salary;