From b4e31c62e24e4a791d02280b1d7c0b72d5ee76a2 Mon Sep 17 00:00:00 2001
From: 0xff-dev <stevenshuang521@gmail.com>
Date: Sun, 8 Sep 2024 14:20:25 +0800
Subject: [PATCH] Add solution and test-cases for problem 809

---
 .../801-900/0809.Expressive-Words/README.md   | 35 ++++++++-----
 .../801-900/0809.Expressive-Words/Solution.go | 52 ++++++++++++++++++-
 .../0809.Expressive-Words/Solution_test.go    | 20 +++----
 3 files changed, 81 insertions(+), 26 deletions(-)

diff --git a/leetcode/801-900/0809.Expressive-Words/README.md b/leetcode/801-900/0809.Expressive-Words/README.md
index cb6c800eb..fcde1ab3a 100644
--- a/leetcode/801-900/0809.Expressive-Words/README.md
+++ b/leetcode/801-900/0809.Expressive-Words/README.md
@@ -1,28 +1,35 @@
 # [809.Expressive Words][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
+Sometimes people repeat letters to represent extra feeling. For example:
+
+- `"hello" -> "heeellooo"`
+- `"hi" -> "hiiii"`
+
+In these strings like `"heeellooo"`, we have groups of adjacent letters that are all the same: `"h"`, `"eee"`, `"ll"`, `"ooo"`.
+
+You are given a string `s` and an array of query strings `words`. A query word is **strectchy** if it can be made to be equal to `s` by any number of applications of the following extension operation: choose a group consisting of characters `c`, and add some number of characters `c` to the group so that the size of the group is **three or more**.
+
+- For example, starting with `"hello"`, we could do an extension on the group `"o"` to get `"hellooo"`, but we cannot get `"helloo"` since the group `"oo"` has a size less than three. Also, we could do another extension like `"ll" -> "lllll"` to get `"helllllooo"`. If `s = "helllllooo"`, then the query word `"hello"` would be **strectchy** because of these two extension operations: `query = "hello" -> "hellooo" -> "helllllooo" = s`.
+
+Return the number of query strings that are **strectchy**.
 
 **Example 1:**
 
 ```
-Input: a = "11", b = "1"
-Output: "100"
+Input: s = "heeellooo", words = ["hello", "hi", "helo"]
+Output: 1
+Explanation: 
+We can extend "e" and "o" in the word "hello" to get "heeellooo".
+We can't extend "helo" to get "heeellooo" because the group "ll" is not size 3 or more.
 ```
 
-## 题意
-> ...
-
-## 题解
+**Example 2:**
 
-### 思路1
-> ...
-Expressive Words
-```go
 ```
-
+Input: s = "zzzzzyyyyy", words = ["zzyy","zy","zyy"]
+Output: 3
+```
 
 ## 结语
 
diff --git a/leetcode/801-900/0809.Expressive-Words/Solution.go b/leetcode/801-900/0809.Expressive-Words/Solution.go
index d115ccf5e..9c137c624 100644
--- a/leetcode/801-900/0809.Expressive-Words/Solution.go
+++ b/leetcode/801-900/0809.Expressive-Words/Solution.go
@@ -1,5 +1,53 @@
 package Solution
 
-func Solution(x bool) bool {
-	return x
+type char809 struct {
+	c  byte
+	cc int
+}
+
+func toChars(s string) []char809 {
+	pre := s[0]
+	c := 1
+	chars := make([]char809, 0)
+	for i := 1; i < len(s); i++ {
+		b := s[i]
+		if b == pre {
+			c++
+			continue
+		}
+		chars = append(chars, char809{c: byte(pre), cc: c})
+		pre = b
+		c = 1
+	}
+	chars = append(chars, char809{c: byte(pre), cc: c})
+	return chars
+}
+func Solution(s string, words []string) int {
+	ans := 0
+	target := toChars(s)
+	for _, word := range words {
+		tmp := toChars(word)
+		if len(tmp) != len(target) {
+			continue
+		}
+		ok := true
+		for i := range len(target) {
+			if target[i].c != tmp[i].c {
+				ok = false
+				break
+			}
+			if target[i].cc < 3 && tmp[i].cc != target[i].cc {
+				ok = false
+				break
+			}
+			if tmp[i].cc > target[i].cc {
+				ok = false
+				break
+			}
+		}
+		if ok {
+			ans++
+		}
+	}
+	return ans
 }
diff --git a/leetcode/801-900/0809.Expressive-Words/Solution_test.go b/leetcode/801-900/0809.Expressive-Words/Solution_test.go
index 14ff50eb4..de51cc3a7 100644
--- a/leetcode/801-900/0809.Expressive-Words/Solution_test.go
+++ b/leetcode/801-900/0809.Expressive-Words/Solution_test.go
@@ -10,30 +10,30 @@ func TestSolution(t *testing.T) {
 	//	测试用例
 	cases := []struct {
 		name   string
-		inputs bool
-		expect bool
+		s      string
+		words  []string
+		expect int
 	}{
-		{"TestCase", true, true},
-		{"TestCase", true, true},
-		{"TestCase", false, false},
+		{"TestCase1", "heeellooo", []string{"hello", "hi", "helo"}, 1},
+		{"TestCase2", "zzzzzyyyyy", []string{"zzyy", "zy", "zyy"}, 3},
 	}
 
 	//	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.words)
 			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.words)
 			}
 		})
 	}
 }
 
-//	压力测试
+// 压力测试
 func BenchmarkSolution(b *testing.B) {
 }
 
-//	使用案列
+// 使用案列
 func ExampleSolution() {
 }