Add solution and test-cases for problem 3461

Author: 0xff-dev

leetcode/3401-3500/3461.Check-If-Digits-Are-Equal-in-String-After-Operations-I/README.md

@@ -1,28 +1,50 @@
 # [3461.Check If Digits Are Equal in String After Operations I][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 string `s` consisting of digits. Perform the following operation repeatedly until the string has **exactly** two digits:
+
+- For each pair of consecutive digits in `s`, starting from the first digit, calculate a new digit as the sum of the two digits **modulo** 10.
+- Replace `s` with the sequence of newly calculated digits, maintaining the order in which they are computed.
+
+Return `true` if the final two digits in `s` are the **same**; otherwise, return `false`.
 
 **Example 1:**
 
 ```
-Input: a = "11", b = "1"
-Output: "100"
+Input: s = "3902"
+
+Output: true
+
+Explanation:
+
+Initially, s = "3902"
+First operation:
+(s[0] + s[1]) % 10 = (3 + 9) % 10 = 2
+(s[1] + s[2]) % 10 = (9 + 0) % 10 = 9
+(s[2] + s[3]) % 10 = (0 + 2) % 10 = 2
+s becomes "292"
+Second operation:
+(s[0] + s[1]) % 10 = (2 + 9) % 10 = 1
+(s[1] + s[2]) % 10 = (9 + 2) % 10 = 1
+s becomes "11"
+Since the digits in "11" are the same, the output is true.
 ```
 
-## 题意
-> ...
-
-## 题解
+**Example 2:**
 
-### 思路1
-> ...
-Check If Digits Are Equal in String After Operations I
-```go
 ```
+Input: s = "34789"
 
+Output: false
+
+Explanation:
+
+Initially, s = "34789".
+After the first operation, s = "7157".
+After the second operation, s = "862".
+After the third operation, s = "48".
+Since '4' != '8', the output is false.
+```
 
 ## 结语
 

leetcode/3401-3500/3461.Check-If-Digits-Are-Equal-in-String-After-Operations-I/Solution.go

@@ -1,5 +1,12 @@
 package Solution
 
-func Solution(x bool) bool {
-	return x
+func Solution(s string) bool {
+	count := len(s) - 2
+	bs := []byte(s)
+	for i := count; i > 0; i-- {
+		for j := 0; j <= i; j++ {
+			bs[j] = byte((int(bs[j]-'0')+int(bs[j+1]-'0'))%10) + '0'
+		}
+	}
+	return bs[0] == bs[1]
 }

leetcode/3401-3500/3461.Check-If-Digits-Are-Equal-in-String-After-Operations-I/Solution_test.go

@@ -10,12 +10,11 @@ func TestSolution(t *testing.T) {
 	//	测试用例
 	cases := []struct {
 		name   string
-		inputs bool
+		inputs string
 		expect bool
 	}{
-		{"TestCase", true, true},
-		{"TestCase", true, true},
-		{"TestCase", false, false},
+		{"TestCase1", "3902", true},
+		{"TestCase2", "34789", false},
 	}
 
 	//	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() {
 }