添加 ArrayReverse.java

ArrayReverse.java

@@ -0,0 +1,21 @@
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+public class ArrayReverse {
+    // ArrayList 反转元素
+    // 双指针解法
+    // 出自 java.util.Collections#reverse
+    public static void main(String[] args) {
+        List<Integer> list = new ArrayList<>(Arrays.asList(1, 2, 3, 4, 5, 6, 7));
+        int size = list.size();
+        Integer x, y;
+        for (int begin = 0, mid = size >> 1, end = size - 1; begin < mid; begin++, end--) {
+            x = list.get(begin);
+            y = list.get(end);
+            list.set(begin, y);
+            list.set(end, x);
+        }
+        System.out.println(list);
+    }
+}