add 1748

README.md

@@ -9,6 +9,7 @@ _If you like this project, please leave me a star._ ★
 |  #  |      Title     |   Solutions   | Video  | Difficulty  | Tag                   
 |-----|----------------|---------------|--------|-------------|-------------
 |1749|[Maximum Absolute Sum of Any Subarray](https://leetcode.com/problems/maximum-absolute-sum-of-any-subarray/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1749.java) ||Medium|Greedy|
+|1748|[Sum of Unique Elements](https://leetcode.com/problems/sum-of-unique-elements/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1748.java) ||Easy|Array, HashTable|
 |1745|[Palindrome Partitioning IV](https://leetcode.com/problems/palindrome-partitioning-iv/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1745.java) ||Hard|String, DP|
 |1743|[Restore the Array From Adjacent Pairs](https://leetcode.com/problems/restore-the-array-from-adjacent-pairs/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1743.java) ||Medium|Greedy|
 |1742|[Maximum Number of Balls in a Box](https://leetcode.com/problems/maximum-number-of-balls-in-a-box/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1742.java) ||Easy|Array|

src/main/java/com/fishercoder/solutions/_1748.java

@@ -0,0 +1,22 @@
+package com.fishercoder.solutions;
+
+import java.util.HashMap;
+import java.util.Map;
+
+public class _1748 {
+    public static class Solution1 {
+        public int sumOfUnique(int[] nums) {
+            Map<Integer, Integer> map = new HashMap<>();
+            int sum = 0;
+            for (int num : nums) {
+                map.put(num, map.getOrDefault(num, 0) + 1);
+            }
+            for (int num : map.keySet()) {
+                if (map.get(num) == 1) {
+                    sum += num;
+                }
+            }
+            return sum;
+        }
+    }
+}