From ba05c26a0018c6db8fd8b56760aab9e99afeaea8 Mon Sep 17 00:00:00 2001
From: Openset <openset.wang@gmail.com>
Date: Sat, 26 Jan 2019 09:24:40 +0800
Subject: [PATCH] Add: Maximum Average Subarray I

---
 .../maximum_average_subarray_i.go             | 16 +++++++++++++
 .../maximum_average_subarray_i_test.go        | 24 +++++++++++++++++++
 2 files changed, 40 insertions(+)

diff --git a/problems/maximum-average-subarray-i/maximum_average_subarray_i.go b/problems/maximum-average-subarray-i/maximum_average_subarray_i.go
index 6571e382a..a0a076275 100644
--- a/problems/maximum-average-subarray-i/maximum_average_subarray_i.go
+++ b/problems/maximum-average-subarray-i/maximum_average_subarray_i.go
@@ -1 +1,17 @@
 package maximum_average_subarray_i
+
+func findMaxAverage(nums []int, k int) float64 {
+	max, sum := 0, 0
+	for i, v := range nums {
+		sum += v
+		if i == k-1 {
+			max = sum
+		} else if i >= k {
+			sum -= nums[i-k]
+		}
+		if sum > max {
+			max = sum
+		}
+	}
+	return float64(max) / float64(k)
+}
diff --git a/problems/maximum-average-subarray-i/maximum_average_subarray_i_test.go b/problems/maximum-average-subarray-i/maximum_average_subarray_i_test.go
index 6571e382a..d3fb3f277 100644
--- a/problems/maximum-average-subarray-i/maximum_average_subarray_i_test.go
+++ b/problems/maximum-average-subarray-i/maximum_average_subarray_i_test.go
@@ -1 +1,25 @@
 package maximum_average_subarray_i
+
+import "testing"
+
+type caseType struct {
+	nums     []int
+	k        int
+	expected float64
+}
+
+func TestFindMaxAverage(t *testing.T) {
+	tests := [...]caseType{
+		{
+			nums:     []int{1, 12, -5, -6, 50, 3},
+			k:        4,
+			expected: 12.75,
+		},
+	}
+	for _, tc := range tests {
+		output := findMaxAverage(tc.nums, tc.k)
+		if output != tc.expected {
+			t.Fatalf("input: %v %v, output: %v, expected: %v", tc.nums, tc.k, output, tc.expected)
+		}
+	}
+}