Merge pull request #988 from 0xff-dev/2343

Add solution and test-cases for problem 2343

Author: 6boris

leetcode/2301-2400/2343.Query-Kth-Smallest-Trimmed-Number/README.md

@@ -1,28 +1,44 @@
 # [2343.Query Kth Smallest Trimmed Number][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** array of strings `nums`, where each string is of **equal length** and consists of only digits.
+
+You are also given a **0-indexed** 2D integer array `queries` where `queries[i] = [ki, trimi]`. For each `queries[i]`, you need to:
+
+- **Trim** each number in `nums` to its **rightmost** `trimi` digits.
+- Determine the **index** of the `kith` smallest trimmed number in `nums`. If two trimmed numbers are equal, the number with the **lower** index is considered to be smaller.
+- Reset each number in `nums` to its original length.
+
+Return an array `answer` of the same length as `queries`, where `answer[i]` is the answer to the `ith` query.
+
+**Note**:
+
+- To trim to the rightmost `x` digits means to keep removing the leftmost digit, until only `x` digits remain.
+- Strings in `nums` may contain leading zeros.
 
 **Example 1:**
 
 ```
-Input: a = "11", b = "1"
-Output: "100"
+Input: nums = ["102","473","251","814"], queries = [[1,1],[2,3],[4,2],[1,2]]
+Output: [2,2,1,0]
+Explanation:
+1. After trimming to the last digit, nums = ["2","3","1","4"]. The smallest number is 1 at index 2.
+2. Trimmed to the last 3 digits, nums is unchanged. The 2nd smallest number is 251 at index 2.
+3. Trimmed to the last 2 digits, nums = ["02","73","51","14"]. The 4th smallest number is 73.
+4. Trimmed to the last 2 digits, the smallest number is 2 at index 0.
+   Note that the trimmed number "02" is evaluated as 2.
 ```
 
-## 题意
-> ...
-
-## 题解
+**Example 2:**
 
-### 思路1
-> ...
-Query Kth Smallest Trimmed Number
-```go
 ```
-
+Input: nums = ["24","37","96","04"], queries = [[2,1],[2,2]]
+Output: [3,0]
+Explanation:
+1. Trimmed to the last digit, nums = ["4","7","6","4"]. The 2nd smallest number is 4 at index 3.
+   There are two occurrences of 4, but the one at index 0 is considered smaller than the one at index 3.
+2. Trimmed to the last 2 digits, nums is unchanged. The 2nd smallest number is 24.
+```
 
 ## 结语
 

leetcode/2301-2400/2343.Query-Kth-Smallest-Trimmed-Number/Solution.go

@@ -1,5 +1,52 @@
 package Solution
 
-func Solution(x bool) bool {
-	return x
+func radixSort2343(nums []string, digit int) [][]string {
+	cache := make([][]string, digit)
+	cur := len(nums[0]) - 1
+	for i := 0; i < digit; i++ {
+		buckets := [10][]string{}
+		for _, num := range nums {
+			key := num[cur] - '0'
+			buckets[key] = append(buckets[key], num)
+		}
+		cur--
+		index := 0
+		for _, bucket := range buckets {
+			for _, n := range bucket {
+				nums[index] = n
+				index++
+			}
+		}
+		tmp := make([]string, len(nums))
+		copy(tmp, nums)
+		cache[i] = tmp
+	}
+	return cache
+}
+
+func Solution(nums []string, queries [][]int) []int {
+	maxDigit := 0
+	indies := make(map[string][]int)
+	for i, n := range nums {
+		if _, ok := indies[n]; !ok {
+			indies[n] = make([]int, 0)
+		}
+		indies[n] = append(indies[n], i)
+	}
+	for _, q := range queries {
+		maxDigit = max(maxDigit, q[1])
+	}
+	cache := radixSort2343(nums, maxDigit)
+	ans := make([]int, len(queries))
+	for i, q := range queries {
+		sortedArray := cache[q[1]-1]
+		index := 0
+		target := sortedArray[q[0]-1]
+		for pre := q[0] - 2; pre >= 0 && sortedArray[pre] == target; pre-- {
+			index++
+		}
+		ans[i] = indies[target][index]
+	}
+
+	return ans
 }

leetcode/2301-2400/2343.Query-Kth-Smallest-Trimmed-Number/Solution_test.go

@@ -9,31 +9,31 @@ import (
 func TestSolution(t *testing.T) {
 	//	测试用例
 	cases := []struct {
-		name   string
-		inputs bool
-		expect bool
+		name    string
+		nums    []string
+		queries [][]int
+		expect  []int
 	}{
-		{"TestCase", true, true},
-		{"TestCase", true, true},
-		{"TestCase", false, false},
+		{"TestCase1", []string{"102", "473", "251", "814"}, [][]int{{1, 1}, {2, 3}, {4, 2}, {1, 2}}, []int{2, 2, 1, 0}},
+		{"TestCase2", []string{"24", "37", "96", "04"}, [][]int{{2, 1}, {2, 2}}, []int{3, 0}},
 	}
 
 	//	开始测试
 	for i, c := range cases {
 		t.Run(c.name+" "+strconv.Itoa(i), func(t *testing.T) {
-			got := Solution(c.inputs)
+			got := Solution(c.nums, c.queries)
 			if !reflect.DeepEqual(got, c.expect) {
-				t.Fatalf("expected: %v, but got: %v, with inputs: %v",
-					c.expect, got, c.inputs)
+				t.Fatalf("expected: %v, but got: %v, with inputs: %v %v",
+					c.expect, got, c.nums, c.queries)
 			}
 		})
 	}
 }
 
-//	压力测试
+// 压力测试
 func BenchmarkSolution(b *testing.B) {
 }
 
-//	使用案列
+// 使用案列
 func ExampleSolution() {
 }