Merge pull request #982 from shellhub/patch1

mergeSortedArrayList

DataStructures/Lists/MergeSortedArrayList.java

@@ -0,0 +1,60 @@
+package DataStructures.Lists;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * @author https://github.com/shellhub
+ */
+
+public class MergeSortedArrayList {
+    public static void main(String[] args) {
+        List<Integer> listA = new ArrayList<>();
+        List<Integer> listB = new ArrayList<>();
+        List<Integer> listC = new ArrayList<>();
+
+        /* init ListA and List B */
+        for (int i = 1; i <= 10; i += 2) {
+            listA.add(i);          /* listA: [1, 3, 5, 7, 9]  */
+            listB.add(i + 1);      /* listB: [2, 4, 6, 8, 10] */
+        }
+
+        /* merge listA and listB to listC */
+        merge(listA, listB, listC);
+
+        System.out.println("listA: " + listA);
+        System.out.println("listB: " + listB);
+        System.out.println("listC: " + listC);
+    }
+
+    /**
+     * merge two sorted ArrayList
+     *
+     * @param listA the first list to merge
+     * @param listB the second list to merge
+     * @param listC the result list after merging
+     */
+    public static void merge(List<Integer> listA, List<Integer> listB, List<Integer> listC) {
+        int pa = 0; /* the index of listA */
+        int pb = 0; /* the index of listB */
+
+        while (pa < listA.size() && pb < listB.size()) {
+            if (listA.get(pa) <= listB.get(pb)) {
+                listC.add(listA.get(pa++));
+            } else {
+                listC.add(listB.get(pb++));
+            }
+        }
+
+        /* copy left element of listA to listC */
+        while (pa < listA.size()) {
+            listC.add(listA.get(pa++));
+        }
+
+        /* copy left element of listB to listC */
+        while (pb < listB.size()) {
+            listC.add(listB.get(pb++));
+        }
+    }
+
+}