restart learn leetcode

Author: Victor An

pom.xml

@@ -7,16 +7,21 @@
     <groupId>me.anduo</groupId>
     <artifactId>jiuzhang</artifactId>
     <version>1.0-SNAPSHOT</version>
-
+    <properties>
+        <maven.compiler.source>11</maven.compiler.source>
+        <maven.compiler.target>11</maven.compiler.target>
+    </properties>
     <build>
         <sourceDirectory>src</sourceDirectory>
         <plugins>
             <plugin>
-                <artifactId>maven-compiler-plugin</artifactId>
-                <configuration>
-                    <source>1.8</source>
-                    <target>1.8</target>
-                </configuration>
+            <groupId>org.apache.maven.plugins</groupId>
+            <artifactId>maven-compiler-plugin</artifactId>
+            <version>3.8.1</version>
+            <configuration>
+                <source>11</source>
+                <target>11</target>
+            </configuration>
             </plugin>
         </plugins>
     </build>

src/solutions/P0001_Two_Sum.java

@@ -0,0 +1,18 @@
+package solutions;
+
+import java.util.HashMap;
+
+public class P0001_Two_Sum {
+
+    public int[] twoSum(int[] nums, int target) {
+        var remainIndexMap = new HashMap<Integer, Integer>();
+        for (int i = 0; i < nums.length; i++) {
+            if (remainIndexMap.containsKey(nums[i])) {
+                return new int[]{remainIndexMap.get(nums[i]), i};
+            } 
+            remainIndexMap.put(target - nums[i], i);
+        }
+        return new int[]{-1, -1};
+    }
+
+}