Add solution 0643

leetcode/0643.Maximum-Average-Subarray-I/643. Maximum Average Subarray I.go

@@ -0,0 +1,21 @@
+package leetcode
+
+func findMaxAverage(nums []int, k int) float64 {
+	sum := 0
+	for _, v := range nums[:k] {
+		sum += v
+	}
+	maxSum := sum
+	for i := k; i < len(nums); i++ {
+		sum = sum - nums[i-k] + nums[i]
+		maxSum = max(maxSum, sum)
+	}
+	return float64(maxSum) / float64(k)
+}
+
+func max(a, b int) int {
+	if a > b {
+		return a
+	}
+	return b
+}

leetcode/0643.Maximum-Average-Subarray-I/643. Maximum Average Subarray I_test.go

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+package leetcode
+
+import (
+	"fmt"
+	"testing"
+)
+
+type question643 struct {
+	para643
+	ans643
+}
+
+// para 是参数
+// one 代表第一个参数
+type para643 struct {
+	nums []int
+	k    int
+}
+
+// ans 是答案
+// one 代表第一个答案
+type ans643 struct {
+	one float64
+}
+
+func Test_Problem643(t *testing.T) {
+
+	qs := []question643{
+
+		{
+			para643{[]int{1, 12, -5, -6, 50, 3}, 4},
+			ans643{12.75},
+		},
+	}
+
+	fmt.Printf("------------------------Leetcode Problem 643------------------------\n")
+
+	for _, q := range qs {
+		_, p := q.ans643, q.para643
+		fmt.Printf("【input】:%v       【output】:%v\n", p, findMaxAverage(p.nums, p.k))
+	}
+	fmt.Printf("\n\n\n")
+}

leetcode/0643.Maximum-Average-Subarray-I/README.md

@@ -0,0 +1,58 @@
+# 643. Maximum Average Subarray I
+
+Added By: halfrost 
+Created Time: Feb 7, 2021 5:07 PM
+Difficulty: Easy
+Link: https://leetcode.com/problems/maximum-average-subarray-i/
+Tags: Array
+
+## 题目
+
+Given an array consisting of `n` integers, find the contiguous subarray of given length `k` that has the maximum average value. And you need to output the maximum average value.
+
+**Example 1:**
+
+```
+Input: [1,12,-5,-6,50,3], k = 4
+Output: 12.75
+Explanation: Maximum average is (12-5-6+50)/4 = 51/4 = 12.75
+```
+
+**Note:**
+
+1. 1 <= `k` <= `n` <= 30,000.
+2. Elements of the given array will be in the range [-10,000, 10,000].
+
+## 题目大意
+
+给定 n 个整数，找出平均数最大且长度为 k 的连续子数组，并输出该最大平均数。
+
+## 解题思路
+
+- 简单题。循环一次，扫描数组过程中累加窗口大小为 k 的元素值。不断更新这个最大值。循环结束求出平均值即可。
+
+## 代码
+
+```go
+package leetcode
+
+func findMaxAverage(nums []int, k int) float64 {
+	sum := 0
+	for _, v := range nums[:k] {
+		sum += v
+	}
+	maxSum := sum
+	for i := k; i < len(nums); i++ {
+		sum = sum - nums[i-k] + nums[i]
+		maxSum = max(maxSum, sum)
+	}
+	return float64(maxSum) / float64(k)
+}
+
+func max(a, b int) int {
+	if a > b {
+		return a
+	}
+	return b
+}
+```