Merge pull request #935 from 0xff-dev/1106

Add solution and test-cases for problem 1106

Author: 6boris

leetcode/1101-1200/1106.Parsing-A-Boolean-Expression/README.md

@@ -1,28 +1,46 @@
 # [1106.Parsing A Boolean Expression][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
+A **boolean expression** is an expression that evaluates to either `true` or `false`. It can be in one of the following shapes:
+
+- `'t'` that evaluates to `true`.
+- `'f'` that evaluates to `false`.
+- `'!(subExpr)'` that evaluates to **the logical NOT** of the inner expression `subExpr`.
+- `'&(subExpr1, subExpr2, ..., subExprn)'` that evaluates to **the logical AND** of the inner expressions `subExpr1, subExpr2, ..., subExprn` where `n >= 1`.
+- `'|(subExpr1, subExpr2, ..., subExprn)'` that evaluates to **the logical OR** of the inner expressions `subExpr1, subExpr2, ..., subExprn` where `n >= 1`.
+
+Given a string `expression` that represents a **boolean expression**, return the evaluation of that expression.
+
+It is **guaranteed** that the given expression is valid and follows the given rules.
 
 **Example 1:**
 
 ```
-Input: a = "11", b = "1"
-Output: "100"
+Input: expression = "&(|(f))"
+Output: false
+Explanation: 
+First, evaluate |(f) --> f. The expression is now "&(f)".
+Then, evaluate &(f) --> f. The expression is now "f".
+Finally, return false.
 ```
 
-## 题意
-> ...
-
-## 题解
+**Example 2:**
 
-### 思路1
-> ...
-Parsing A Boolean Expression
-```go
 ```
+Input: expression = "|(f,f,f,t)"
+Output: true
+Explanation: The evaluation of (false OR false OR false OR true) is true.
+```
+
+**Example 3:**
 
+```
+Input: expression = "!(&(f,t))"
+Output: true
+Explanation: 
+First, evaluate &(f,t) --> (false AND true) --> false --> f. The expression is now "!(f)".
+Then, evaluate !(f) --> NOT false --> true. We return true.
+```
 
 ## 结语
 

leetcode/1101-1200/1106.Parsing-A-Boolean-Expression/Solution.go

@@ -1,5 +1,63 @@
 package Solution
 
-func Solution(x bool) bool {
-	return x
+type tmp1106 struct {
+	op byte
+
+	f, t bool
+}
+
+func Solution(expression string) bool {
+	l := len(expression)
+	stack := make([]tmp1106, l)
+	index := -1
+	f, t := false, false
+	i := 0
+	for ; i < l; i++ {
+		cur := expression[i]
+		if cur == '!' || cur == '|' || cur == '&' {
+			index++
+			stack[index] = tmp1106{
+				cur, f, t,
+			}
+			t, f = false, false
+			i++
+			continue
+		}
+		if cur == ')' {
+			top := stack[index]
+			index--
+			if top.op == '!' {
+				if t {
+					t, f = false, true
+					f = true
+				} else {
+					t, f = true, false
+				}
+			}
+			if top.op == '|' {
+				if t {
+					t, f = true, false
+				} else {
+					t, f = false, true
+				}
+			}
+			if top.op == '&' {
+				if f {
+					t, f = false, true
+				} else {
+					t, f = true, false
+				}
+			}
+			t = t || top.t
+			f = f || top.f
+			continue
+		}
+		if cur == 'f' {
+			f = true
+		}
+		if cur == 't' {
+			t = true
+		}
+	}
+	return t
 }

leetcode/1101-1200/1106.Parsing-A-Boolean-Expression/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", "&(|(f))", false},
+		{"TestCase2", "|(f,f,f,t)", true},
+		{"TestCase3", "!(&(f,t))", true},
+		{"TestCase4", "|(&(t,f,t),!(t))", false},
 	}
 
 	//	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() {
 }