added tests for findMaxAverage

Author: MaryNfs

Go/Leetcode/find_max_average/find_max_average_test.go

@@ -2,6 +2,20 @@ package find_max_average
 
 import "testing"
 
-func TestSolve(t *testing.T) {
-	t.Fatal("write tests")
+func TestFindMaxAverage(t *testing.T) {
+	cases := []struct {
+		nums []int
+		k    int
+		out  float64
+	}{
+		{[]int{1, 12, -5, -6, 50, 3}, 4, 12.75000},
+		{[]int{5}, 1, 5.00000},
+		{[]int{-1}, 1, -1.00000},
+	}
+	for _, c := range cases {
+		res := findMaxAverage(c.nums, c.k)
+		if res != c.out {
+			t.Errorf("findMaxAverage(%v, %v)=%v, but expected %v", c.nums, c.k, res, c.out)
+		}
+	}
 }

Go/Leetcode/find_max_average/q.md

@@ -1,12 +1,21 @@
-# find_max_average
+# 643. Maximum Average Subarray I
 
 ## Problem
 
-Paste the problem description here.
-
+You are given an integer array nums consisting of n elements, and an integer k.
+Find a contiguous subarray whose length is equal to k that has the maximum average value and return this value. Any answer with a calculation error less than 10-5 will be accepted
 ## Examples
+Example 1:
+Input: nums = [1,12,-5,-6,50,3], k = 4
+Output: 12.75000
+Explanation: Maximum average is (12 - 5 - 6 + 50) / 4 = 51 / 4 = 12.75
+
+Example 2:
+Input: nums = [5], k = 1
+Output: 5.00000
 
 ## Notes
 - Constraints:
-- Edge cases:
-- Complexity:
+n == nums.length
+1 <= k <= n <= 105
+-104 <= nums[i] <= 104