Add solution and test-cases for problem 831

Author: 0xff-dev

leetcode/801-900/0831.Masking-Personal-Information/README.md

@@ -1,28 +1,71 @@
 # [831.Masking Personal Information][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 a personal information string `s`, representing either an **email address** or a **phone number**. Return the **masked** personal information using the below rules.
+
+**Email address**:
+
+An email address is:
+
+- A **name** consisting of uppercase and lowercase English letters, followed by
+- The `'@'` symbol, followed by
+- The **domain** consisting of uppercase and lowercase English letters with a dot `'.'` somewhere in the middle (not the first or last character).
+
+To mask an email:
+
+- The uppercase letters in the **name** and **domain** must be converted to lowercase letters.
+- The middle letters of the **name** (i.e., all but the first and last letters) must be replaced by 5 asterisks `"*****"`.
+
+**Phone number**:
+
+A phone number is formatted as follows:
+
+- The phone number contains 10-13 digits.
+- The last 10 digits make up the **local number**.
+- The remaining 0-3 digits, in the beginning, make up the **country code**.
+- **Separation characters** from the set `{'+', '-', '(', ')', ' '}` separate the above digits in some way.
+
+To mask a phone number:
+
+- Remove all **separation characters**.
+- The masked phone number should have the form:
+
+    - `"***-***-XXXX"` if the country code has 0 digits.
+    - `"+*-***-***-XXXX"` if the country code has 1 digit.
+    - `"+**-***-***-XXXX"` if the country code has 2 digits.
+    - `"+***-***-***-XXXX"` if the country code has 3 digits.
+
+- `"XXXX"` is the last 4 digits of the **local number**.
+
 
 **Example 1:**
 
 ```
-Input: a = "11", b = "1"
-Output: "100"
+Input: s = "LeetCode@LeetCode.com"
+Output: "l*****e@leetcode.com"
+Explanation: s is an email address.
+The name and domain are converted to lowercase, and the middle of the name is replaced by 5 asterisks.
 ```
 
-## 题意
-> ...
-
-## 题解
+**Example 2:**
 
-### 思路1
-> ...
-Masking Personal Information
-```go
 ```
+Input: s = "AB@qq.com"
+Output: "a*****b@qq.com"
+Explanation: s is an email address.
+The name and domain are converted to lowercase, and the middle of the name is replaced by 5 asterisks.
+Note that even though "ab" is 2 characters, it still must have 5 asterisks in the middle.
+```
+
+**Example 3:**
 
+```
+Input: s = "1(234)567-890"
+Output: "***-***-7890"
+Explanation: s is a phone number.
+There are 10 digits, so the local number is 10 digits and the country code is 0 digits.
+Thus, the resulting masked number is "***-***-7890".
+```
 
 ## 结语
 

leetcode/801-900/0831.Masking-Personal-Information/Solution.go

@@ -1,5 +1,65 @@
 package Solution
 
-func Solution(x bool) bool {
-	return x
+import "strings"
+
+func maskEmail(email string) string {
+	buf := strings.Builder{}
+	cur := email[0]
+	if cur >= 'A' && cur <= 'Z' {
+		cur += uint8(32)
+	}
+	buf.WriteByte(cur)
+	buf.WriteString("*****")
+	i := 1
+	for ; i < len(email) && email[i] != '@'; i++ {
+	}
+	cur = email[i-1]
+	if cur >= 'A' && cur <= 'Z' {
+		cur += uint8(32)
+	}
+	buf.WriteByte(cur)
+	buf.WriteString(strings.ToLower(email[i:]))
+	return buf.String()
+}
+
+func maskPhone(phone string) string {
+	buf := make([]byte, 0)
+	i := len(phone) - 1
+
+	for ; i >= 0; i-- {
+		if phone[i] >= '0' && phone[i] <= '9' {
+			buf = append(buf, phone[i])
+		}
+	}
+	ans := strings.Builder{}
+	diff := len(buf) - 10
+	if r := diff; r > 0 {
+		ans.WriteByte('+')
+		for ; r > 0; r-- {
+			ans.WriteByte('*')
+		}
+		ans.WriteByte('-')
+	}
+	// 1, 2, 3, 4-5, 6, 7-8, 9, 10-11, 12,13
+	index := len(buf) - diff - 1
+	count := 3
+	for ; index > 3; index-- {
+		ans.WriteByte('*')
+		count--
+		if count == 0 {
+			ans.WriteByte('-')
+			count = 3
+		}
+	}
+	for ; index >= 0; index-- {
+		ans.WriteByte(buf[index])
+	}
+	return ans.String()
+}
+
+func Solution(s string) string {
+	if strings.Contains(s, "@") {
+		return maskEmail(s)
+	}
+	return maskPhone(s)
 }

leetcode/801-900/0831.Masking-Personal-Information/Solution_test.go

@@ -10,12 +10,12 @@ func TestSolution(t *testing.T) {
 	//	测试用例
 	cases := []struct {
 		name   string
-		inputs bool
-		expect bool
+		inputs string
+		expect string
 	}{
-		{"TestCase", true, true},
-		{"TestCase", true, true},
-		{"TestCase", false, false},
+		{"TestCase1", "LeetCode@LeetCode.com", "l*****e@leetcode.com"},
+		{"TestCase2", "AB@qq.com", "a*****b@qq.com"},
+		{"TestCase3", "1(234)567-890", "***-***-7890"},
 	}
 
 	//	开始测试
@@ -30,10 +30,10 @@ 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() {
 }