Add solution and test-cases for problem 2901

Author: 0xff-dev

leetcode/2901-3000/2901.Longest-Unequal-Adjacent-Groups-Subsequence-II/README.md

@@ -1,28 +1,58 @@
 # [2901.Longest Unequal Adjacent Groups Subsequence II][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 array `words`, and an array `groups`, both arrays having length `n`.
+
+The **hamming distance** between two strings of equal length is the number of positions at which the corresponding characters are **different**.
+
+You need to select the **longest subsequence** from an array of indices `[0, 1, ..., n - 1]`, such that for the subsequence denoted as `[i0, i1, ..., ik-1]` having length `k`, the following holds:
+
+- For **adjacent** indices in the subsequence, their corresponding groups are **unequal**, i.e., `groups[ij] != groups[ij+1]`, for each `j` where `0 < j + 1 < k`.
+- `words[ij]` and `words[ij+1]` are **equal** in length, and the **hamming distance** between them is `1`, where `0 < j + 1 < k`, for all indices in the subsequence.
+
+Return a string array containing the words corresponding to the indices **(in order)** in the selected subsequence. If there are multiple answers, return any of them.
+
+**Note**: strings in `words` may be **unequal** in length.
 
 **Example 1:**
 
 ```
-Input: a = "11", b = "1"
-Output: "100"
-```
+Input: words = ["bab","dab","cab"], groups = [1,2,2]
+
+Output: ["bab","cab"]
+
+Explanation: A subsequence that can be selected is [0,2].
+
+groups[0] != groups[2]
+words[0].length == words[2].length, and the hamming distance between them is 1.
+So, a valid answer is [words[0],words[2]] = ["bab","cab"].
 
-## 题意
-> ...
+Another subsequence that can be selected is [0,1].
 
-## 题解
+groups[0] != groups[1]
+words[0].length == words[1].length, and the hamming distance between them is 1.
+So, another valid answer is [words[0],words[1]] = ["bab","dab"].
 
-### 思路1
-> ...
-Longest Unequal Adjacent Groups Subsequence II
-```go
+It can be shown that the length of the longest subsequence of indices that satisfies the conditions is 2.
 ```
 
+**Example 2:**
+
+```
+Input: words = ["a","b","c","d"], groups = [1,2,3,4]
+
+Output: ["a","b","c","d"]
+
+Explanation: We can select the subsequence [0,1,2,3].
+
+It satisfies both conditions.
+
+Hence, the answer is [words[0],words[1],words[2],words[3]] = ["a","b","c","d"].
+
+It has the longest length among all subsequences of indices that satisfy the conditions.
+
+Hence, it is the only answer.
+```
 
 ## 结语
 

leetcode/2901-3000/2901.Longest-Unequal-Adjacent-Groups-Subsequence-II/Solution.go

@@ -1,5 +1,43 @@
 package Solution
 
-func Solution(x bool) bool {
-	return x
+func hammingDistance(a, b string) bool {
+	if len(a) != len(b) {
+		return false
+	}
+	d := 0
+	for i := range len(a) {
+		if a[i] != b[i] {
+			d++
+			if d > 1 {
+				return false
+			}
+		}
+	}
+	return d == 1
+}
+
+func Solution(words []string, groups []int) []string {
+	l, index := 1, 0
+	dp := make([][2]int, len(words))
+	dp[0] = [2]int{1, -1} // 前一个
+	for i := 1; i < len(words); i++ {
+		dp[i] = [2]int{1, -1}
+		for pre := i - 1; pre >= 0; pre-- {
+			if groups[i] != groups[pre] && hammingDistance(words[i], words[pre]) {
+				if dp[pre][0]+1 > dp[i][0] {
+					dp[i] = [2]int{dp[pre][0] + 1, pre}
+				}
+			}
+		}
+		if dp[i][0] > l {
+			l = dp[i][0]
+			index = i
+		}
+	}
+	ans := make([]string, l)
+	for i := l - 1; i >= 0; i-- {
+		ans[i] = words[index]
+		index = dp[index][1]
+	}
+	return ans
 }

leetcode/2901-3000/2901.Longest-Unequal-Adjacent-Groups-Subsequence-II/Solution_test.go

@@ -10,30 +10,30 @@ func TestSolution(t *testing.T) {
 	//	测试用例
 	cases := []struct {
 		name   string
-		inputs bool
-		expect bool
+		words  []string
+		groups []int
+		expect []string
 	}{
-		{"TestCase", true, true},
-		{"TestCase", true, true},
-		{"TestCase", false, false},
+		{"TestCase1", []string{"bab", "dab", "cab"}, []int{1, 2, 2}, []string{"bab", "dab"}},
+		{"TestCase2", []string{"a", "b", "c", "d"}, []int{1, 2, 3, 4}, []string{"a", "b", "c", "d"}},
 	}
 
 	//	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.words, c.groups)
 			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.words, c.groups)
 			}
 		})
 	}
 }
 
-//	压力测试
+// 压力测试
 func BenchmarkSolution(b *testing.B) {
 }
 
-//	使用案列
+// 使用案列
 func ExampleSolution() {
 }