Wed Apr 19 07:38:40 UTC 2023 inscode

Main.java

-class Main {
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+import static java.util.stream.Collectors.toList;
+public class Main {
   public static void main(String[] args) {
-    System.out.println("Hello world!");
+    List<String> list1 = Arrays.asList("A", "B", "C");
+    List<String> list2 = Arrays.asList("1", "2");
+    List<String> result = product(list1, list2);
+    result.forEach(System.out::println);
+}
+
+/**
+ * @param lists 可变长度参数列表
+ * */
+public static List<String> product(List<String>... lists) {
+    List<String> temp = new ArrayList<>();
+    for (List<String> list : lists) {
+        if (temp.isEmpty()) {
+            temp = list;
+        } else {
+            // stream流 flatMap 和 map 方法
+            temp = temp.stream().flatMap(o1 -> list.stream().map(o2 -> o1 + " " + o2)).collect(toList());
+        }
+    }
+    return temp;
   }
 }
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