Merge pull request #783 from 0xff-dev/869

Add solution and test-cases for problem 869

Author: 6boris

leetcode/801-900/0869.Reordered-Power-of-2/README.md

@@ -1,28 +1,23 @@
 # [869.Reordered Power of 2][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 `n`. We reorder the digits in any order (including the original order) such that the leading digit is not zero.
+
+Return `true` if and only if we can do this so that the resulting number is a power of two.
 
 **Example 1:**
 
 ```
-Input: a = "11", b = "1"
-Output: "100"
+Input: n = 1
+Output: true
 ```
 
-## 题意
-> ...
-
-## 题解
+**Example 2:**
 
-### 思路1
-> ...
-Reordered Power of 2
-```go
 ```
-
+Input: n = 10
+Output: false
+```
 
 ## 结语
 

leetcode/801-900/0869.Reordered-Power-of-2/Solution.go

@@ -1,5 +1,36 @@
 package Solution
 
-func Solution(x bool) bool {
-	return x
+func toKey(n int) [10]int {
+	tmp := [10]int{}
+	for n > 0 {
+		cur := n % 10
+		tmp[cur]++
+		n /= 10
+	}
+	return tmp
+}
+func Solution(n int) bool {
+	if n&(n-1) == 0 {
+		return true
+	}
+
+	cache := map[[10]int]struct{}{}
+	key := toKey(n)
+	end := 0
+	for i := 9; i >= 0; i-- {
+		count := key[i]
+		for ; count > 0; count-- {
+			end = end*10 + i
+		}
+	}
+	shift := 0
+	cur := 1
+	for cur <= end {
+		t := toKey(cur)
+		cache[t] = struct{}{}
+		shift++
+		cur = 1 << shift
+	}
+	_, ok := cache[toKey(n)]
+	return ok
 }

leetcode/801-900/0869.Reordered-Power-of-2/Solution_test.go

@@ -10,12 +10,13 @@ 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", 1, true},
+		{"TestCase2", 10, false},
+		{"TestCase3", 46, true},
+		{"TestCase4", 125, true},
 	}
 
 	//	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() {
 }