Merge pull request #836 from 0xff-dev/678

Add solution and test-cases for problem 678

Author: 6boris

leetcode/601-700/0678.Valid-Parenthesis-String/README.md

@@ -1,28 +1,35 @@
 # [678.Valid Parenthesis 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
+Given a string `s` containing only three types of characters: `'('`, `')'` and `'*'`, return `true` if `s` is **valid**.
+
+The following rules define a **valid** string:
+
+- Any left parenthesis `'('` must have a corresponding right parenthesis `')'`.
+- Any right parenthesis `')'` must have a corresponding left parenthesis `'('`.
+- Left parenthesis `'('` must go before the corresponding right parenthesis `')'`.
+- `'*'` could be treated as a single right parenthesis `')'` or a single left parenthesis `'('` or an empty string `""`.
 
 **Example 1:**
 
 ```
-Input: a = "11", b = "1"
-Output: "100"
+Input: s = "()"
+Output: true
 ```
 
-## 题意
-> ...
-
-## 题解
+**Example 2:**
 
-### 思路1
-> ...
-Valid Parenthesis String
-```go
 ```
+Input: s = "(*)"
+Output: true
+```
+
+**Example 3:**
 
+```
+Input: s = "(*))"
+Output: true
+```
 
 ## 结语
 

leetcode/601-700/0678.Valid-Parenthesis-String/Solution.go

@@ -1,5 +1,50 @@
 package Solution
 
-func Solution(x bool) bool {
-	return x
+func Solution(s string) bool {
+	// 尝试将*替换成 “”，(, )，来做判断, 就是一个dfs+cache，但是问题是，*可能会非常多
+	// 例如******* 一共100个，每个搜有三种选择，就离谱了啊, 先试试
+	l := len(s)
+	cache := make([][]int8, l+1)
+	for i := 0; i <= l; i++ {
+		cache[i] = make([]int8, l+1)
+		for j := 0; j <= l; j++ {
+			cache[i][j] = -1
+		}
+	}
+	var dfs func(int, int) bool
+	dfs = func(index, left int) bool {
+		if index == l {
+			return left == 0
+		}
+
+		if cache[index][left] != -1 {
+			return cache[index][left] == 1
+		}
+
+		r := false
+		if s[index] == '*' {
+			// 如果 将* 设置为(
+			r = r || dfs(index+1, left+1)
+			// 注意只有说有(的时候，设置为)才是正确的
+			if left > 0 {
+				r = r || dfs(index+1, left-1)
+			}
+			r = r || dfs(index+1, left)
+		} else {
+			if s[index] == '(' {
+				r = dfs(index+1, left+1)
+			} else {
+				if left > 0 {
+					r = dfs(index+1, left-1)
+				}
+			}
+		}
+		if r {
+			cache[index][left] = 1
+		} else {
+			cache[index][left] = 0
+		}
+		return r
+	}
+	return dfs(0, 0)
 }

leetcode/601-700/0678.Valid-Parenthesis-String/Solution_test.go

@@ -10,12 +10,13 @@ func TestSolution(t *testing.T) {
 	//	测试用例
 	cases := []struct {
 		name   string
-		inputs bool
+		inputs string
 		expect bool
 	}{
-		{"TestCase", true, true},
-		{"TestCase", true, true},
-		{"TestCase", false, false},
+		{"TestCase1", "()", true},
+		{"TestCase2", "(*)", true},
+		{"TestCase3", "(*))", true},
+		{"TestCase4", "************************************************************", true},
 	}
 
 	//	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() {
 }