Add solution and test-cases for problem 1471

Author: 0xff-dev

leetcode/1401-1500/1471.The-k-Strongest-Values-in-an-Array/README.md

@@ -0,0 +1,47 @@
+# [1471.The k Strongest Values in an Array][title]
+
+## Description
+Given an array of integers `arr` and an integer `k`.
+
+A value `arr[i]` is said to be stronger than a value `arr[j]` if `|arr[i] - m| > |arr[j] - m|` where `m` is the **median** of the array.
+If `|arr[i] - m| == |arr[j] - m|`, then `arr[i]` is said to be stronger than `arr[j]` if `arr[i] > arr[j]`.
+
+Return a list of the strongest `k` values in the array. return the answer **in any arbitrary order**.
+
+**Median** is the middle value in an ordered integer list. More formally, if the length of the list is n, the median is the element in position `((n - 1) / 2)` in the sorted list **(0-indexed)**.
+
+- For `arr = [6, -3, 7, 2, 11]`, `n = 5` and the median is obtained by sorting the array `arr = [-3, 2, 6, 7, 11]` and the median is `arr[m]` where `m = ((5 - 1) / 2) = 2`. The median is `6`.
+- For `arr = [-7, 22, 17, 3]`, `n = 4` and the median is obtained by sorting the array `arr = [-7, 3, 17, 22]` and the median is `arr[m]` where `m = ((4 - 1) / 2) = 1`. The median is `3`.
+
+**Example 1:**
+
+```
+Input: arr = [1,2,3,4,5], k = 2
+Output: [5,1]
+Explanation: Median is 3, the elements of the array sorted by the strongest are [5,1,4,2,3]. The strongest 2 elements are [5, 1]. [1, 5] is also accepted answer.
+Please note that although |5 - 3| == |1 - 3| but 5 is stronger than 1 because 5 > 1.
+```
+
+**Example 2:**
+
+```
+Input: arr = [1,1,3,5,5], k = 2
+Output: [5,5]
+Explanation: Median is 3, the elements of the array sorted by the strongest are [5,5,1,1,3]. The strongest 2 elements are [5, 5].
+```
+
+**Example 3:**
+
+```
+Input: arr = [6,7,11,7,6,8], k = 5
+Output: [11,8,6,6,7]
+Explanation: Median is 7, the elements of the array sorted by the strongest are [11,8,6,6,7,7].
+Any permutation of [11,8,6,6,7] is accepted.
+```
+
+## 结语
+
+如果你同我一样热爱数据结构、算法、LeetCode，可以关注我 GitHub 上的 LeetCode 题解：[awesome-golang-algorithm][me]
+
+[title]: https://leetcode.com/problems/the-k-strongest-values-in-an-array
+[me]: https://github.com/kylesliu/awesome-golang-algorithm

leetcode/1401-1500/1471.The-k-Strongest-Values-in-an-Array/Solution.go

@@ -1,5 +1,30 @@
 package Solution
 
-func Solution(x bool) bool {
-	return x
+import "sort"
+
+func Solution(arr []int, k int) []int {
+	l := len(arr)
+	sort.Ints(arr)
+	median := arr[(l-1)/2]
+	ai, bi := 0, l-1
+	ans := make([]int, k)
+	index := 0
+	for ; k > 0; k, index = k-1, index+1 {
+		a := arr[ai] - median
+		b := arr[bi] - median
+		if a < 0 {
+			a = -a
+		}
+		if b < 0 {
+			b = -b
+		}
+		if a > b || (a == b && arr[ai] > arr[bi]) {
+			ans[index] = arr[ai]
+			ai++
+			continue
+		}
+		ans[index] = arr[bi]
+		bi--
+	}
+	return ans
 }

leetcode/1401-1500/1471.The-k-Strongest-Values-in-an-Array/Solution_test.go

@@ -10,30 +10,31 @@ func TestSolution(t *testing.T) {
 	//	测试用例
 	cases := []struct {
 		name   string
-		inputs bool
-		expect bool
+		arr    []int
+		k      int
+		expect []int
 	}{
-		{"TestCase", true, true},
-		{"TestCase", true, true},
-		{"TestCase", false, false},
+		{"TestCase1", []int{1, 2, 3, 4, 5}, 2, []int{5, 1}},
+		{"TestCase2", []int{1, 1, 3, 5, 5}, 2, []int{5, 5}},
+		{"TestCase3", []int{6, 7, 11, 7, 6, 8}, 5, []int{11, 8, 6, 6, 7}},
 	}
 
 	//	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.arr, c.k)
 			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.arr, c.k)
 			}
 		})
 	}
 }
 
-//	压力测试
+// 压力测试
 func BenchmarkSolution(b *testing.B) {
 }
 
-//	使用案列
+// 使用案列
 func ExampleSolution() {
 }