Add solution and test-cases for problem 2149

leetcode/2101-2200/2149.Rearrange-Array-Elements-by-Sign/README.md

@@ -1,28 +1,36 @@
 # [2149.Rearrange Array Elements by Sign][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 a **0-indexed** integer array nums of **even** length consisting of an **equal** number of positive and negative integers.
+
+You should **rearrange** the elements of nums such that the modified array follows the given conditions:
+
+1. Every **consecutive pair** of integers have **opposite signs**.
+2. For all integers with the same sign, the **order** in which they were present in `nums` is **preserved**.
+3. The rearranged array begins with a positive integer.
+
+Return the modified array after rearranging the elements to satisfy the aforementioned conditions.
 
 **Example 1:**
 
 ```
-Input: a = "11", b = "1"
-Output: "100"
+Input: nums = [3,1,-2,-5,2,-4]
+Output: [3,-2,1,-5,2,-4]
+Explanation:
+The positive integers in nums are [3,1,2]. The negative integers are [-2,-5,-4].
+The only possible way to rearrange them such that they satisfy all conditions is [3,-2,1,-5,2,-4].
+Other ways such as [1,-2,2,-5,3,-4], [3,1,2,-2,-5,-4], [-2,3,-5,1,-4,2] are incorrect because they do not satisfy one or more conditions.
 ```
 
-## 题意
-> ...
+**Example 2:**
 
-## 题解
-
-### 思路1
-> ...
-Rearrange Array Elements by Sign
-```go
 ```
-
+Input: nums = [-1,1]
+Output: [1,-1]
+Explanation:
+1 is the only positive integer and -1 the only negative integer in nums.
+So nums is rearranged to [1,-1].
+```
 
 ## 结语
 

leetcode/2101-2200/2149.Rearrange-Array-Elements-by-Sign/Solution.go

@@ -1,5 +1,23 @@
 package Solution
 
-func Solution(x bool) bool {
-return x
+func Solution(nums []int) []int {
+l := len(nums)
+neg := make([]int, l/2)
+pos := make([]int, l/2)
+ans := make([]int, l)
+ai, bi := 0, 0
+for _, n := range nums {
+if n < 0 {
+neg[ai] = n
+ai++
+continue
+}
+pos[bi] = n
+bi++
+}
+for i := 0; i < l; i += 2 {
+ans[i] = pos[i/2]
+ans[i+1] = neg[i/2]
+}
+return ans
 }

leetcode/2101-2200/2149.Rearrange-Array-Elements-by-Sign/Solution_test.go

@@ -10,12 +10,11 @@ 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{3, 1, -2, -5, 2, -4}, []int{3, -2, 1, -5, 2, -4}},
+{"TestCase2", []int{-1, 1}, []int{1, -1}},
 }
 
 //	开始测试
@@ -30,10 +29,10 @@ 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() {
 }