Merge pull request #1203 from 0xff-dev/3335

Add solution and test-cases for problem 3335

Author: 6boris

leetcode/3301-3400/3335.Total-Characters-in-String-After-Transformations-I/README.md

@@ -1,28 +1,58 @@
 # [3335.Total Characters in String After Transformations 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` and an integer `t`, representing the number of **transformations** to perform. In one **transformation**, every character in `s` is replaced according to the following rules:
+
+- If the character is `'z'`, replace it with the string `"ab"`.
+- Otherwise, replace it with the next character in the alphabet. For example, `'a'` is replaced with `'b'`, `'b'` is replaced with `'c'`, and so on.
+
+Return the **length** of the resulting string after **exactly** `t` transformations.
+
+Since the answer may be very large, return it **modulo** `10^9 + 7`.
 
 **Example 1:**
 
 ```
-Input: a = "11", b = "1"
-Output: "100"
+Input: s = "abcyy", t = 2
+
+Output: 7
+
+Explanation:
+
+First Transformation (t = 1):
+'a' becomes 'b'
+'b' becomes 'c'
+'c' becomes 'd'
+'y' becomes 'z'
+'y' becomes 'z'
+String after the first transformation: "bcdzz"
+Second Transformation (t = 2):
+'b' becomes 'c'
+'c' becomes 'd'
+'d' becomes 'e'
+'z' becomes "ab"
+'z' becomes "ab"
+String after the second transformation: "cdeabab"
+Final Length of the string: The string is "cdeabab", which has 7 characters.
 ```
 
-## 题意
-> ...
+**Example 2:**
 
-## 题解
-
-### 思路1
-> ...
-Total Characters in String After Transformations I
-```go
 ```
+Input: s = "azbk", t = 1
+
+Output: 5
 
+Explanation:
+
+First Transformation (t = 1):
+'a' becomes 'b'
+'z' becomes "ab"
+'b' becomes 'c'
+'k' becomes 'l'
+String after the first transformation: "babcl"
+Final Length of the string: The string is "babcl", which has 5 characters.
+```
 
 ## 结语
 

leetcode/3301-3400/3335.Total-Characters-in-String-After-Transformations-I/Solution.go

@@ -1,5 +1,29 @@
 package Solution
 
-func Solution(x bool) bool {
-	return x
+const mod = 1000000007
+
+func Solution(s string, t int) int {
+	count := [26]int{}
+	for _, b := range s {
+		count[b-'a']++
+	}
+	for ; t > 0; t-- {
+		tmp := [26]int{}
+		// a, b, c, d .... z
+		// count是前一轮的变化
+		z := count[25]
+		for i := 25; i > 0; i-- {
+			tmp[i] = count[i-1]
+		}
+		tmp[0] = z
+		tmp[1] = (tmp[1] + z) % mod
+		for i := range 26 {
+			count[i] = tmp[i]
+		}
+	}
+	ans := 0
+	for i := range 26 {
+		ans = (ans + count[i]) % mod
+	}
+	return ans
 }

leetcode/3301-3400/3335.Total-Characters-in-String-After-Transformations-I/Solution_test.go

@@ -10,30 +10,31 @@ func TestSolution(t *testing.T) {
 	//	测试用例
 	cases := []struct {
 		name   string
-		inputs bool
-		expect bool
+		s      string
+		tt     int
+		expect int
 	}{
-		{"TestCase", true, true},
-		{"TestCase", true, true},
-		{"TestCase", false, false},
+		{"TestCase1", "abcyy", 2, 7},
+		{"TestCase2", "azbk", 1, 5},
+		{"TestCase3", "jqktcurgdvlibczdsvnsg", 7517, 79033769},
 	}
 
 	//	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.s, c.tt)
 			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",
+					c.expect, got, c.s, c.tt)
 			}
 		})
 	}
 }
 
-//	压力测试
+// 压力测试
 func BenchmarkSolution(b *testing.B) {
 }
 
-//	使用案列
+// 使用案列
 func ExampleSolution() {
 }