Merge pull request #1235 from 0xff-dev/2016

Add solution and test-cases for problem 2016

Author: 6boris

leetcode/2001-2100/2016.Maximum-Difference-Between-Increasing-Elements/README.md

@@ -1,28 +1,38 @@
 # [2016.Maximum Difference Between Increasing Elements][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 **0-indexed** integer array `nums` of size `n`, find the **maximum difference** between `nums[i]` and `nums[j]` (i.e., `nums[j] - nums[i]`), such that `0 <= i < j < n` and `nums[i] < nums[j]`.
+
+Return the **maximum difference**. If no such `i` and `j` exists, return `-1`.
+
 **Example 1:**
 
 ```
-Input: a = "11", b = "1"
-Output: "100"
+Input: nums = [7,1,5,4]
+Output: 4
+Explanation:
+The maximum difference occurs with i = 1 and j = 2, nums[j] - nums[i] = 5 - 1 = 4.
+Note that with i = 1 and j = 0, the difference nums[j] - nums[i] = 7 - 1 = 6, but i > j, so it is not valid.
 ```
 
-## 题意
-> ...
-
-## 题解
+**Example 2:**
 
-### 思路1
-> ...
-Maximum Difference Between Increasing Elements
-```go
 ```
+Input: nums = [9,4,3,2]
+Output: -1
+Explanation:
+There is no i and j such that i < j and nums[i] < nums[j].
+```
+
+**Example 3:**
 
+```
+Input: nums = [1,5,2,10]
+Output: 9
+Explanation:
+The maximum difference occurs with i = 0 and j = 3, nums[j] - nums[i] = 10 - 1 = 9.
+```
 
 ## 结语
 

leetcode/2001-2100/2016.Maximum-Difference-Between-Increasing-Elements/Solution.go

@@ -1,5 +1,22 @@
 package Solution
 
-func Solution(x bool) bool {
-	return x
+func Solution(nums []int) int {
+	minNumbers := make([]int, len(nums))
+	minNumbers[0] = nums[0]
+	for i := 1; i < len(nums); i++ {
+		minNumbers[i] = min(minNumbers[i-1], nums[i])
+	}
+	ans := -1
+	var diff, a int
+	for i := len(nums) - 1; i > 0; i-- {
+		a = minNumbers[i-1]
+		if a >= nums[i] {
+			continue
+		}
+		diff = nums[i] - a
+		if ans == -1 || ans < diff {
+			ans = diff
+		}
+	}
+	return ans
 }

leetcode/2001-2100/2016.Maximum-Difference-Between-Increasing-Elements/Solution_test.go

@@ -10,12 +10,12 @@ 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", []int{7, 1, 5, 4}, 4},
+		{"TestCase2", []int{9, 4, 3, 2}, -1},
+		{"TestCase3", []int{1, 5, 2, 10}, 9},
 	}
 
 	//	开始测试
@@ -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() {
 }