Add solution and test-cases for problem 1331

leetcode/1301-1400/1331.Rank-Transform-of-an-Array/README.md

@@ -1,28 +1,36 @@
 # [1331.Rank Transform of an Array][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 array of integers `arr`, replace each element with its rank.
+
+The rank represents how large the element is. The rank has the following rules:
+
+- Rank is an integer starting from 1.
+- The larger the element, the larger the rank. If two elements are equal, their rank must be the same.
+- Rank should be as small as possible.
 
 **Example 1:**
 
 ```
-Input: a = "11", b = "1"
-Output: "100"
+Input: arr = [40,10,20,30]
+Output: [4,1,2,3]
+Explanation: 40 is the largest element. 10 is the smallest. 20 is the second smallest. 30 is the third smallest.
 ```
 
-## 题意
-> ...
-
-## 题解
+**Example 2:**
 
-### 思路1
-> ...
-Rank Transform of an Array
-```go
 ```
+Input: arr = [100,100,100]
+Output: [1,1,1]
+Explanation: Same elements share the same rank.
+```
+
+**Example 3:**
 
+```
+Input: arr = [37,12,28,9,100,56,80,5,12]
+Output: [5,3,4,2,8,6,7,1,3]
+```
 
 ## 结语
 

leetcode/1301-1400/1331.Rank-Transform-of-an-Array/Solution.go

@@ -1,5 +1,30 @@
 package Solution
 
-func Solution(x bool) bool {
-	return x
+import "sort"
+
+type index [][2]int
+
+func Solution(arr []int) []int {
+	l := len(arr)
+	ans := make([]int, l)
+	if l == 0 {
+		return ans
+	}
+	slices := make(index, l)
+	for i := range l {
+		slices[i] = [2]int{i, arr[i]}
+	}
+	sort.Slice(slices, func(i, j int) bool {
+		return slices[i][1] < slices[j][1]
+	})
+
+	rank := 1
+	ans[slices[0][0]] = rank
+	for i := 1; i < l; i++ {
+		if slices[i][1] != slices[i-1][1] {
+			rank++
+		}
+		ans[slices[i][0]] = rank
+	}
+	return ans
 }

leetcode/1301-1400/1331.Rank-Transform-of-an-Array/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{40, 10, 20, 30}, []int{4, 1, 2, 3}},
+		{"TestCase2", []int{100, 100, 100}, []int{1, 1, 1}},
+		{"TestCase3", []int{37, 12, 28, 9, 100, 56, 80, 5, 12}, []int{5, 3, 4, 2, 8, 6, 7, 1, 3}},
 	}
 
 	//	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() {
 }