Add solution and test-cases for problem 3577

Author: 0xff-dev

leetcode/3501-3600/3577.Count-the-Number-of-Computer-Unlocking-Permutations/README.md

@@ -1,28 +1,53 @@
 # [3577.Count the Number of Computer Unlocking Permutations][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 given an array `complexity` of length `n`.
+
+There are `n` **locked** computers in a room with labels from 0 to `n - 1`, each with its own **unique** password. The password of the computer `i` has a `complexity complexity[i]`.
+
+The password for the computer labeled 0 is **already** decrypted and serves as the root. All other computers must be unlocked using it or another previously unlocked computer, following this information:
+
+- You can decrypt the password for the computer `i` using the password for computer `j`, where `j` is **any** integer less than `i` with a lower complexity. (i.e. `j < i` and `complexity[j] < complexity[i]`)
+- To decrypt the password for computer `i`, you must have already unlocked a computer `j` such that `j < i` and `complexity[j] < complexity[i]`.
+
+Find the number of permutations of `[0, 1, 2, ..., (n - 1)]` that represent a valid order in which the computers can be unlocked, starting from computer 0 as the only initially unlocked one.
+
+Since the answer may be large, return it **modulo** `10^9 + 7`.
+
+**Note** that the password for the computer **with label** 0 is decrypted, and not the computer with the first position in the permutation.
 
 **Example 1:**
 
 ```
-Input: a = "11", b = "1"
-Output: "100"
-```
+Input: complexity = [1,2,3]
 
-## 题意
-> ...
+Output: 2
 
-## 题解
+Explanation:
+
+The valid permutations are:
+
+[0, 1, 2]
+Unlock computer 0 first with root password.
+Unlock computer 1 with password of computer 0 since complexity[0] < complexity[1].
+Unlock computer 2 with password of computer 1 since complexity[1] < complexity[2].
+[0, 2, 1]
+Unlock computer 0 first with root password.
+Unlock computer 2 with password of computer 0 since complexity[0] < complexity[2].
+Unlock computer 1 with password of computer 0 since complexity[0] < complexity[1].
+```
+
+**Example 2:**
 
-### 思路1
-> ...
-Count the Number of Computer Unlocking Permutations
-```go
 ```
+Input: complexity = [3,3,3,4,4,4]
 
+Output: 0
+
+Explanation:
+
+There are no possible permutations which can unlock all computers.
+```
 
 ## 结语
 

leetcode/3501-3600/3577.Count-the-Number-of-Computer-Unlocking-Permutations/Solution.go

@@ -1,5 +1,17 @@
 package Solution
 
-func Solution(x bool) bool {
-	return x
+func Solution(complexity []int) int {
+	n := len(complexity)
+	for i := 1; i < n; i++ {
+		if complexity[i] <= complexity[0] {
+			return 0
+		}
+	}
+
+	ans := 1
+	mod := 1000000007
+	for i := 2; i < n; i++ {
+		ans = ans * i % mod
+	}
+	return ans
 }

leetcode/3501-3600/3577.Count-the-Number-of-Computer-Unlocking-Permutations/Solution_test.go

@@ -10,12 +10,11 @@ func TestSolution(t *testing.T) {
 	//	测试用例
 	cases := []struct {
 		name   string
-		inputs bool
-		expect bool
+		inputs []int
+		expect int
 	}{
-		{"TestCase", true, true},
-		{"TestCase", true, true},
-		{"TestCase", false, false},
+		{"TestCase1", []int{1, 2, 3}, 2},
+		{"TestCase2", []int{3, 3, 3, 4, 4, 4}, 0},
 	}
 
 	//	开始测试
@@ -30,10 +29,10 @@ func TestSolution(t *testing.T) {
 	}
 }
 
-//	压力测试
+// 压力测试
 func BenchmarkSolution(b *testing.B) {
 }
 
-//	使用案列
+// 使用案列
 func ExampleSolution() {
 }