Merge pull request #654 from 0xff-dev/1239

Add solution and test-cases for problem 1239

leetcode/1201-1300/1239.Maximum-Length-of-a-Concatenated-String-with-Unique-Characters/README.md

@@ -1,28 +1,42 @@
 # [1239.Maximum Length of a Concatenated String with Unique Characters][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 an array of strings `arr`. A string s is formed by the **concatenation** of a **subsequence** of arr that has **unique characters**.
+
+Return the **maximum** possible length of `s`.
+
+A **subsequence** is an array that can be derived from another array by deleting some or no elements without changing the order of the remaining elements.
 
 **Example 1:**
 
 ```
-Input: a = "11", b = "1"
-Output: "100"
+Input: arr = ["un","iq","ue"]
+Output: 4
+Explanation: All the valid concatenations are:
+- ""
+- "un"
+- "iq"
+- "ue"
+- "uniq" ("un" + "iq")
+- "ique" ("iq" + "ue")
+Maximum length is 4.
 ```
 
-## 题意
-> ...
-
-## 题解
+**Example 2:**
 
-### 思路1
-> ...
-Maximum Length of a Concatenated String with Unique Characters
-```go
 ```
+Input: arr = ["cha","r","act","ers"]
+Output: 6
+Explanation: Possible longest valid concatenations are "chaers" ("cha" + "ers") and "acters" ("act" + "ers").
+```
+
+**Example 3:**
 
+```
+Input: arr = ["abcdefghijklmnopqrstuvwxyz"]
+Output: 26
+Explanation: The only string in arr has all 26 characters.
+```
 
 ## 结语
 

leetcode/1201-1300/1239.Maximum-Length-of-a-Concatenated-String-with-Unique-Characters/Solution.go

@@ -1,5 +1,61 @@
 package Solution
 
-func Solution(x bool) bool {
-	return x
+func Solution(arr []string) int {
+	filter := make([]string, 0)
+	for _, x := range arr {
+		tmp := [26]bool{}
+		add := true
+		for _, b := range []byte(x) {
+			if tmp[b-'a'] {
+				add = false
+				break
+			}
+			tmp[b-'a'] = true
+		}
+		if add {
+			filter = append(filter, x)
+		}
+	}
+	if len(filter) == 0 {
+		return 0
+	}
+
+	ans := 0
+	var (
+		subset    func(int, int, int, [26]bool)
+		canSelect func(a [26]bool, b string) bool
+	)
+	canSelect = func(a [26]bool, b string) bool {
+		for _, v := range b {
+			if a[v-'a'] {
+				return false
+			}
+		}
+		return true
+	}
+	subset = func(index, subsetLen, strLen int, path [26]bool) {
+		if subsetLen == 0 {
+			if strLen > ans {
+				ans = strLen
+			}
+			return
+		}
+		if index >= len(filter) {
+			return
+		}
+		if canSelect(path, filter[index]) {
+			for _, v := range filter[index] {
+				path[v-'a'] = true
+			}
+			subset(index+1, subsetLen-1, strLen+len(filter[index]), path)
+			for _, v := range filter[index] {
+				path[v-'a'] = false
+			}
+		}
+		subset(index+1, subsetLen, strLen, path)
+	}
+	for l := 1; l <= len(filter); l++ {
+		subset(0, l, 0, [26]bool{})
+	}
+	return ans
 }

leetcode/1201-1300/1239.Maximum-Length-of-a-Concatenated-String-with-Unique-Characters/Solution_test.go

@@ -10,12 +10,13 @@ func TestSolution(t *testing.T) {
 	//	测试用例
 	cases := []struct {
 		name   string
-		inputs bool
-		expect bool
+		inputs []string
+		expect int
 	}{
-		{"TestCase", true, true},
-		{"TestCase", true, true},
-		{"TestCase", false, false},
+		{"TestCase1", []string{"un", "iq", "ue"}, 4},
+		{"TestCase2", []string{"cha", "r", "act", "ers"}, 6},
+		{"TestCase3", []string{"abcdefghijklmnopqrstuvwxyz"}, 26},
+		{"TestCase4", []string{"abcdefghijklm", "bcdefghijklmn", "cdefghijklmno", "defghijklmnop", "efghijklmnopq", "fghijklmnopqr", "ghijklmnopqrs", "hijklmnopqrst", "ijklmnopqrstu", "jklmnopqrstuv", "klmnopqrstuvw", "lmnopqrstuvwx", "mnopqrstuvwxy", "nopqrstuvwxyz", "opqrstuvwxyza", "pqrstuvwxyzab"}, 26},
 	}
 
 	//	开始测试
@@ -30,10 +31,10 @@ 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() {
 }