fix:range issue (#496)

codes/go/chapter_sorting/counting_sort.go

@@ -11,7 +11,7 @@ type CountingSort struct{}
 func countingSortNaive(nums []int) {
 	// 1. 统计数组最大元素 m
 	m := 0
-	for num := range nums {
+	for _, num := range nums {
 		if num > m {
 			m = num
 		}
@@ -36,7 +36,7 @@ func countingSortNaive(nums []int) {
 func countingSort(nums []int) {
 	// 1. 统计数组最大元素 m
 	m := 0
-	for num := range nums {
+	for _, num := range nums {
 		if num > m {
 			m = num
 		}