Merge pull request #1125 from 0xff-dev/2375

Add solution and test-cases for problem  2375

Author: 6boris

leetcode/2301-2400/2375.Construct-Smallest-Number-From-DI-String/README.md

@@ -1,28 +1,38 @@
 # [2375.Construct Smallest Number From DI String][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 **0-indexed** string `pattern` of length `n` consisting of the characters `'I'` meaning **increasing** and `'D'` meaning **decreasing**.
+
+A **0-indexed** string `num` of length `n + 1` is created using the following conditions:
+
+- `num` consists of the digits `'1'` to `'9'`, where each digit is used **at most** once.
+- If `pattern[i] == 'I'`, then `num[i] < num[i + 1]`.
+- If `pattern[i] == 'D'`, then `num[i] > num[i + 1]`.
+
+Return the lexicographically **smallest** possible string `num` that meets the conditions.
 
 **Example 1:**
 
 ```
-Input: a = "11", b = "1"
-Output: "100"
+Input: pattern = "IIIDIDDD"
+Output: "123549876"
+Explanation:
+At indices 0, 1, 2, and 4 we must have that num[i] < num[i+1].
+At indices 3, 5, 6, and 7 we must have that num[i] > num[i+1].
+Some possible values of num are "245639871", "135749862", and "123849765".
+It can be proven that "123549876" is the smallest possible num that meets the conditions.
+Note that "123414321" is not possible because the digit '1' is used more than once.
 ```
 
-## 题意
-> ...
+**Example 2:**
 
-## 题解
-
-### 思路1
-> ...
-Construct Smallest Number From DI String
-```go
 ```
-
+Input: pattern = "DDD"
+Output: "4321"
+Explanation:
+Some possible values of num are "9876", "7321", and "8742".
+It can be proven that "4321" is the smallest possible num that meets the conditions.
+```
 
 ## 结语
 

leetcode/2301-2400/2375.Construct-Smallest-Number-From-DI-String/Solution.go

@@ -1,5 +1,29 @@
 package Solution
 
-func Solution(x bool) bool {
-	return x
+func Solution(pattern string) string {
+	res := make([]byte, len(pattern)+1)
+	for i := range res {
+		res[i] = '0'
+	}
+
+	index := byte('1')
+	for i := 0; i < len(pattern); i++ {
+		if pattern[i] == 'D' {
+			continue
+		}
+		res[i] = index
+		index++
+		for pre := i - 1; pre >= 0 && res[pre] == '0'; pre-- {
+			res[pre] = index
+			index++
+		}
+	}
+
+	res[len(pattern)] = index
+	index++
+	for pre := len(pattern) - 1; pre >= 0 && res[pre] == '0'; pre-- {
+		res[pre] = index
+		index++
+	}
+	return string(res)
 }

leetcode/2301-2400/2375.Construct-Smallest-Number-From-DI-String/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 string
+		expect string
 	}{
-		{"TestCase", true, true},
-		{"TestCase", true, true},
-		{"TestCase", false, false},
+		{"TestCase1", "IIIDIDDD", "123549876"},
+		{"TestCase2", "DDD", "4321"},
 	}
 
 	//	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() {
 }