Add solution and test-cases for problem 954

Author: 0xff-dev

leetcode/901-1000/0954.Array-of-Doubled-Pairs/README.md

@@ -1,28 +1,29 @@
 # [954.Array of Doubled Pairs][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 an integer array of even length `arr`, return `true` if it is possible to reorder arr such that `arr[2 * i + 1] = 2 * arr[2 * i]` for every `0 <= i < len(arr) / 2`, or `false` otherwise.
 
 **Example 1:**
 
 ```
-Input: a = "11", b = "1"
-Output: "100"
+Input: arr = [3,1,3,6]
+Output: false
 ```
 
-## 题意
-> ...
-
-## 题解
+**Example 2:**
 
-### 思路1
-> ...
-Array of Doubled Pairs
-```go
+```
+Input: arr = [2,1,2,6]
+Output: false
 ```
 
+**Example 3:**
+
+```
+Input: arr = [4,-2,2,-4]
+Output: true
+Explanation: We can take two groups, [-2,-4] and [2,4] to form [-2,-4,2,4] or [2,4,-2,-4].
+```
 
 ## 结语
 

leetcode/901-1000/0954.Array-of-Doubled-Pairs/Solution.go

@@ -1,5 +1,57 @@
 package Solution
 
-func Solution(x bool) bool {
-	return x
+import "sort"
+
+type index954 struct {
+	idx    int
+	indies []int
+}
+
+func Solution(arr []int) bool {
+	sort.Slice(arr, func(i, j int) bool {
+		a := arr[i]
+		b := arr[j]
+		if a < 0 {
+			a = -a
+		}
+		if b < 0 {
+			b = -b
+		}
+		return a < b
+	})
+
+	cnt := make(map[int]index954)
+	for i, n := range arr {
+		if _, ok := cnt[n]; !ok {
+			cnt[n] = index954{idx: 0, indies: []int{}}
+		}
+		ic := cnt[n]
+		ic.indies = append(ic.indies, i)
+		cnt[n] = ic
+	}
+
+	skip := make([]bool, len(arr))
+	index := 0
+	for ; index < len(arr) && arr[index] == 0; index++ {
+	}
+	if index&1 == 1 {
+		return false
+	}
+	for ; index < len(arr); index++ {
+		if skip[index] {
+			continue
+		}
+		target := arr[index] * 2
+		v, ok := cnt[target]
+		if !ok {
+			return false
+		}
+		if v.idx == len(v.indies) {
+			return false
+		}
+		skip[v.indies[v.idx]] = true
+		v.idx++
+		cnt[target] = v
+	}
+	return true
 }

leetcode/901-1000/0954.Array-of-Doubled-Pairs/Solution_test.go

@@ -10,12 +10,12 @@ func TestSolution(t *testing.T) {
 	//	测试用例
 	cases := []struct {
 		name   string
-		inputs bool
+		inputs []int
 		expect bool
 	}{
-		{"TestCase", true, true},
-		{"TestCase", true, true},
-		{"TestCase", false, false},
+		{"TestCase1", []int{3, 1, 3, 6}, false},
+		{"TestCase2", []int{2, 1, 2, 6}, false},
+		{"TestCase3", []int{4, -2, 2, -4}, true},
 	}
 
 	//	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() {
 }