Merge pull request #1232 from 0xff-dev/3310

Add solution and test-cases for problem 3310

Author: 6boris

leetcode/3301-3400/3310.Remove-Methods-From-Project/1.png

@@ -1,28 +1,57 @@
 # [3310.Remove Methods From Project][title]
 
-> [!WARNING|style:flat]
-> This question is temporarily unanswered if you have good ideas. Welcome to [Create Pull Request PR](https://github.com/kylesliu/awesome-golang-algorithm)
-
 ## Description
+You are maintaining a project that has `n` methods numbered from `0` to `n - 1`.
+
+You are given two integers `n` and `k`, and a 2D integer array `invocations`, where `invocations[i] = [ai, bi]` indicates that method `ai` invokes method `bi`.
+
+There is a known bug in method `k`. Method `k`, along with any method invoked by it, either **directly** or **indirectly**, are considered **suspicious** and we aim to remove them.
+
+A group of methods can only be removed if no method **outside** the group invokes any methods **within** it.
+
+Return an array containing all the remaining methods after removing all the **suspicious** methods. You may return the answer in any order. If it is not possible to remove **all** the suspicious methods, **none** should be removed.
+
+**Example 1:**  
+
+![1](./1.png)
+
+```
+Input: n = 4, k = 1, invocations = [[1,2],[0,1],[3,2]]
+
+Output: [0,1,2,3]
 
-**Example 1:**
+Explanation:
 
+Method 2 and method 1 are suspicious, but they are directly invoked by methods 3 and 0, which are not suspicious. We return all elements without removing anything.
 ```
-Input: a = "11", b = "1"
-Output: "100"
+
+**Example 2:**  
+
+![2](./2.png)
+
+```
+Input: n = 5, k = 0, invocations = [[1,2],[0,2],[0,1],[3,4]]
+
+Output: [3,4]
+
+Explanation:
+
+Methods 0, 1, and 2 are suspicious and they are not directly invoked by any other method. We can remove them.
 ```
 
-## 题意
-> ...
+**Example 3:**  
 
-## 题解
+![3](./3.png)
 
-### 思路1
-> ...
-Remove Methods From Project
-```go
 ```
+Input: n = 3, k = 2, invocations = [[1,2],[0,1],[2,0]]
+
+Output: []
 
+Explanation:
+
+All methods are suspicious. We can remove them.
+```
 
 ## 结语
 

leetcode/3301-3400/3310.Remove-Methods-From-Project/2.png

@@ -1,5 +1,71 @@
 package Solution
 
-func Solution(x bool) bool {
-	return x
+type unionFind3310 struct {
+	father []int
+}
+
+func (u *unionFind3310) findFather(x int) int {
+	if x != u.father[x] {
+		u.father[x] = u.findFather(u.father[x])
+	}
+	return u.father[x]
+}
+
+func (u *unionFind3310) union(x, y int) {
+	fx := u.findFather(x)
+	fy := u.findFather(y)
+	if fx < fy {
+		u.father[fy] = fx
+	} else {
+		u.father[fx] = fy
+	}
+}
+
+func Solution(n int, k int, invocations [][]int) []int {
+	u := unionFind3310{father: make([]int, n)}
+	for i := range n {
+		u.father[i] = i
+	}
+	relations := make(map[int][]int)
+	removed := make([]bool, n)
+	for _, in := range invocations {
+		u.union(in[0], in[1])
+		relations[in[0]] = append(relations[in[0]], in[1])
+	}
+	// 然后通过dfs将所有的问题方法都标记出来
+	// 这个组的数据是有问题的
+	problemGroup := u.findFather(k)
+	// 将所有的数据开始做标记
+	removed[k] = true
+	var dfs func(int)
+	used := map[int]bool{
+		k: true,
+	}
+	dfs = func(cur int) {
+		removed[cur] = true
+		for _, rel := range relations[cur] {
+			if used[rel] {
+				continue
+			}
+			used[rel] = true
+			dfs(rel)
+		}
+	}
+	dfs(k)
+	var res, keep []int
+
+	for i := range n {
+		f := u.findFather(i)
+		if f != problemGroup {
+			res = append(res, i)
+			continue
+		}
+		if !removed[i] {
+			for j := range n {
+				keep = append(keep, j)
+			}
+			return keep
+		}
+	}
+	return res
 }

leetcode/3301-3400/3310.Remove-Methods-From-Project/3.png

@@ -9,31 +9,32 @@ import (
 func TestSolution(t *testing.T) {
 	//	测试用例
 	cases := []struct {
-		name   string
-		inputs bool
-		expect bool
+		name        string
+		n, k        int
+		invocations [][]int
+		expect      []int
 	}{
-		{"TestCase", true, true},
-		{"TestCase", true, true},
-		{"TestCase", false, false},
+		{"TestCase1", 4, 1, [][]int{{1, 2}, {0, 1}, {3, 2}}, []int{0, 1, 2, 3}},
+		{"TestCase2", 5, 0, [][]int{{1, 2}, {0, 2}, {0, 1}, {3, 4}}, []int{3, 4}},
+		{"TestCase3", 3, 2, [][]int{{1, 2}, {0, 1}, {2, 0}}, nil},
 	}
 
 	//	开始测试
 	for i, c := range cases {
 		t.Run(c.name+" "+strconv.Itoa(i), func(t *testing.T) {
-			got := Solution(c.inputs)
+			got := Solution(c.n, c.k, c.invocations)
 			if !reflect.DeepEqual(got, c.expect) {
-				t.Fatalf("expected: %v, but got: %v, with inputs: %v",
-					c.expect, got, c.inputs)
+				t.Fatalf("expected: %v, but got: %v, with inputs: %v %v %v",
+					c.expect, got, c.n, c.k, c.invocations)
 			}
 		})
 	}
 }
 
-//	压力测试
+// 压力测试
 func BenchmarkSolution(b *testing.B) {
 }
 
-//	使用案列
+// 使用案列
 func ExampleSolution() {
 }