Add PriorityQueue And Shuffle Demo

XGerry · XGerry · commit 5acbb7a7916f · 2018-12-13T21:24:51.000+08:00
diff --git a/src/MapDemo.java b/src/MapDemo.java
@@ -18,6 +18,7 @@ public static void main(String[] args) {
                 map.values()) {
             System.out.println(value);
         }
+
         //第二种
         System.out.println("通过Map.entrySet使用iterator遍历key和value：");
         Iterator<Map.Entry<String, String>> iterator = map.entrySet().iterator();
@@ -31,6 +32,9 @@ public static void main(String[] args) {
                 ) {
             System.out.println("key=" + entry.getKey() + " and value=" + entry.getValue());
         }
+        //第四种：尤其推荐
+        map.forEach((k, v) -> System.out.println("Key=" + k + ",Value=" + v));
+
         Vector vector = new Vector();
         vector.add("11");
 
diff --git a/src/PriorityQueueDemo.java b/src/PriorityQueueDemo.java
@@ -0,0 +1,20 @@
+import java.time.LocalDate;
+import java.util.PriorityQueue;
+
+public class PriorityQueueDemo {
+    public static void main(String[] args) {
+        PriorityQueue<LocalDate> pq = new PriorityQueue<>();
+        pq.add(LocalDate.of(1906, 12, 9));
+        pq.add(LocalDate.of(1815, 12, 10));
+        pq.add(LocalDate.of(1903, 12, 3));
+        pq.add(LocalDate.of(1910, 6, 22));
+        System.out.println("Iterating over elements...");
+        for (LocalDate date : pq) {
+            System.out.println(date);
+        }
+        System.out.println("Removing elements....");
+        while (!pq.isEmpty()) {
+            System.out.println(pq.remove());
+        }
+    }
+}
diff --git a/src/ShuffleDemo.java b/src/ShuffleDemo.java
@@ -0,0 +1,17 @@
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+//随机的混排列表中元素的顺序
+public class ShuffleDemo {
+    public static void main(String[] args) {
+        List<Integer> numbers = new ArrayList<>();
+        for (int i = 0; i <= 49; i++) {
+            numbers.add(i);
+        }
+        Collections.shuffle(numbers);
+        List<Integer> winningCombination = numbers.subList(0, 6);
+        Collections.sort(winningCombination);
+        System.out.println(winningCombination);
+    }
+}
