first

course/9-maps/exercises/4-maps_count/code.go

@@ -0,0 +1,39 @@
+package main
+
+import (
+	"crypto/md5"
+	"fmt"
+	"io"
+)
+
+func getCounts(userIDs []string) map[string]int {
+	// ?
+}
+
+// don't edit below this line
+
+func test(userIDs []string, ids []string) {
+	fmt.Printf("Generating counts for %v user IDs...\n", len(userIDs))
+
+	counts := getCounts(userIDs)
+	fmt.Println("Counts from select IDs:")
+	for _, k := range ids {
+		v := counts[k]
+		fmt.Printf(" - %s: %d\n", k, v)
+	}
+	fmt.Println("=====================================")
+}
+
+func main() {
+	userIDs := []string{}
+	for i := 0; i < 10000; i++ {
+		h := md5.New()
+		io.WriteString(h, fmt.Sprint(i))
+		key := fmt.Sprintf("%x", h.Sum(nil))
+		userIDs = append(userIDs, key[:2])
+	}
+
+	test(userIDs, []string{"00", "ff", "dd"})
+	test(userIDs, []string{"aa", "12", "32"})
+	test(userIDs, []string{"bb", "33"})
+}