Merge pull request #1088 from 0xff-dev/2185

Add solution and test-cases for problem 2185

Author: 6boris

leetcode/2101-2200/2185.Counting-Words-With-a-Given-Prefix/README.md

@@ -1,28 +1,27 @@
 # [2185.Counting Words With a Given Prefix][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 `words` and a string `pref`.
+
+Return the number of strings in `words` that contain `pref` as a **prefix**.
+
+A **prefix** of a string `s` is any leading contiguous substring of `s`.
 
 **Example 1:**
 
 ```
-Input: a = "11", b = "1"
-Output: "100"
+Input: words = ["pay","attention","practice","attend"], pref = "at"
+Output: 2
+Explanation: The 2 strings that contain "at" as a prefix are: "attention" and "attend".
 ```
 
-## 题意
-> ...
+**Example 2:**
 
-## 题解
-
-### 思路1
-> ...
-Counting Words With a Given Prefix
-```go
 ```
-
+Input: words = ["leetcode","win","loops","success"], pref = "code"
+Output: 0
+Explanation: There are no strings that contain "code" as a prefix.
+```
 
 ## 结语
 

leetcode/2101-2200/2185.Counting-Words-With-a-Given-Prefix/Solution.go

@@ -1,5 +1,37 @@
 package Solution
 
-func Solution(x bool) bool {
-	return x
+type trieNode2185 struct {
+	c     int
+	child [26]*trieNode2185
+}
+
+func insert(tree *trieNode2185, word string) {
+	cur := tree
+	for _, b := range word {
+		idx := b - 'a'
+		if cur.child[idx] == nil {
+			cur.child[idx] = &trieNode2185{}
+		}
+		cur.child[idx].c++
+		cur = cur.child[idx]
+	}
+}
+
+func search(tree *trieNode2185, target string) int {
+	cur := tree
+	for _, b := range target {
+		if cur.child[b-'a'] == nil {
+			return 0
+		}
+		cur = cur.child[b-'a']
+	}
+	return cur.c
+}
+
+func Solution(words []string, pref string) int {
+	tree := &trieNode2185{}
+	for _, w := range words {
+		insert(tree, w)
+	}
+	return search(tree, pref)
 }

leetcode/2101-2200/2185.Counting-Words-With-a-Given-Prefix/Solution_test.go

@@ -10,18 +10,18 @@ func TestSolution(t *testing.T) {
 	//	测试用例
 	cases := []struct {
 		name   string
-		inputs bool
-		expect bool
+		inputs []string
+		prefix string
+		expect int
 	}{
-		{"TestCase", true, true},
-		{"TestCase", true, true},
-		{"TestCase", false, false},
+		{"TestCase1", []string{"pay", "attention", "practice", "attend"}, "at", 2},
+		{"TestCase2", []string{"leetcode", "win", "loops", "success"}, "code", 0},
 	}
 
 	//	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.inputs, c.prefix)
 			if !reflect.DeepEqual(got, c.expect) {
 				t.Fatalf("expected: %v, but got: %v, with inputs: %v",
 					c.expect, got, c.inputs)
@@ -30,10 +30,10 @@ 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() {
 }