add: leetcode 1984 solution

leetcode/1984.Minimum-Difference-Between-Highest-and-Lowest-of-K-Scores/1984.Minimum Difference Between Highest and Lowest of K Scores.go

@@ -0,0 +1,18 @@
+package leetcode
+
+import "sort"
+
+func minimumDifference(nums []int, k int) int {
+	sort.Ints(nums)
+	minDiff := 100000 + 1
+	for i := 0; i < len(nums); i++ {
+		if i+k-1 >= len(nums) {
+			break
+		}
+		diff := nums[i+k-1] - nums[i]
+		if diff < minDiff {
+			minDiff = diff
+		}
+	}
+	return minDiff
+}