添加0001.两数之和 Java版本

problems/0001.两数之和.md

@@ -85,7 +85,24 @@ public:
 
 
 Java：
-
+```java
+public int[] twoSum(int[] nums, int target) {
+    int[] res = new int[2];
+    if(nums == null || nums.length == 0){
+        return res;
+    }
+    Map<Integer, Integer> map = new HashMap<>();
+    for(int i = 0; i < nums.length; i++){
+        int temp = target - nums[i];
+        if(map.containsKey(temp)){
+            res[1] = i;
+            res[0] = map.get(temp);
+        }
+        map.put(nums[i], i);
+    }
+    return res;
+}
+```
 
 Python：