Merge pull request #983 from 0xff-dev/670

Add solution and test-cases for problem 670

Author: 6boris

leetcode/601-700/0670.Maximum-Swap/README.md

@@ -1,28 +1,25 @@
 # [670.Maximum Swap][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 integer `num`. You can swap two digits at most once to get the maximum valued number.
+
+Return the maximum valued number you can get.
 
 **Example 1:**
 
 ```
-Input: a = "11", b = "1"
-Output: "100"
+Input: num = 2736
+Output: 7236
+Explanation: Swap the number 2 and the number 7.
 ```
 
-## 题意
-> ...
-
-## 题解
+**Example 2:**
 
-### 思路1
-> ...
-Maximum Swap
-```go
 ```
-
+Input: num = 9973
+Output: 9973
+Explanation: No swap.
+```
 
 ## 结语
 

leetcode/601-700/0670.Maximum-Swap/Solution.go

@@ -1,5 +1,28 @@
 package Solution
 
-func Solution(x bool) bool {
-	return x
+func Solution(num int) int {
+	digits := make([]uint8, 0)
+	for num > 0 {
+		mod := num % 10
+		digits = append(digits, uint8(mod))
+		num /= 10
+	}
+	index := len(digits) - 1
+	for ; index > 0; index-- {
+		targetIndex := index
+		for pre := index - 1; pre >= 0; pre-- {
+			if digits[pre] >= digits[targetIndex] {
+				targetIndex = pre
+			}
+		}
+		if targetIndex != index && digits[targetIndex] != digits[index] {
+			digits[targetIndex], digits[index] = digits[index], digits[targetIndex]
+			break
+		}
+	}
+	ans := 0
+	for i := len(digits) - 1; i >= 0; i-- {
+		ans = ans*10 + int(digits[i])
+	}
+	return ans
 }

leetcode/601-700/0670.Maximum-Swap/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 int
+		expect int
 	}{
-		{"TestCase", true, true},
-		{"TestCase", true, true},
-		{"TestCase", false, false},
+		{"TestCase1", 2736, 7236},
+		{"TestCase2", 9973, 9973},
+		{"TestCase3", 1993, 9913},
+		{"TestCase4", 98368, 98863},
 	}
 
 	//	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() {
 }