Merge pull request #3 from bingyuhuang/master

new algorithm: twosum java && fix bug :add package
sherlockblaze · Dec 17, 2018 · 3b878e1 · 3b878e1
2 parents 14793b0 + 48ab5ff
commit 3b878e1
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Showing 2 changed files with 30 additions and 1 deletion.
diff --git a/knowledge/algorithms/combat/code/java/AddTwoNumbers.java b/knowledge/algorithms/combat/code/java/AddTwoNumbers.java
@@ -1,5 +1,7 @@
+import java.util.LinkedList;
+import java.util.List;
 public class AddTwoNumbers {
-	public static void addTwoNumber(List<Integer> num1, List<Integer> num2) {
+	public static List<Integer> addTwoNumber(List<Integer> num1, List<Integer> num2) {
 
         List<Integer> result = new LinkedList<Integer>();
         int i = num1.size();
@@ -19,5 +21,6 @@ public static void addTwoNumber(List<Integer> num1, List<Integer> num2) {
                 break;
             }
         }
+        return result;
     }
 }
diff --git a/knowledge/algorithms/combat/code/java/TwoSum.java b/knowledge/algorithms/combat/code/java/TwoSum.java
@@ -0,0 +1,26 @@
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * find two numbers in the arrays
+ * where a number adds the other equals the target
+ */
+public class TwoSum {
+
+    public static int[] twoSum (int[] arrays, int target) {
+        Map<Integer, Integer> indexMap = new HashMap<Integer, Integer>(arrays.length);
+        int[] result = new int[2];
+        for (int i = 0; i < arrays.length; i++) {
+            if (indexMap.get(arrays[i]) != null){
+                continue;
+            }
+            indexMap.put(arrays[i], i);
+            if (indexMap.get(target - arrays[i]) != null) {
+                result[0] = indexMap.get(arrays[i]);
+                result[1] = indexMap.get(target - arrays[i]);
+                break;
+            }
+        }
+        return result;
+    }
+}