commit

Author: bryanfks-dev

137. Single Number II.java

@@ -0,0 +1,22 @@
+class Solution {
+    public int singleNumber(int[] nums) {
+        // Create a hashmap to track numbers
+        Map<Integer, Integer> map = new HashMap();
+
+        // Push all elements into hashmap
+        for (int num : nums) {
+            // Put the value as how many number found in array
+            map.put(num, map.getOrDefault(num, 0) + 1);
+        }
+
+        for (Map.Entry<Integer, Integer> entry : map.entrySet()) {
+            // If the key value is 1 means, the number only appeared once in the array
+            if (entry.getValue() == 1) {
+                return entry.getKey();
+            }
+        }
+
+        // Not found
+        return -1;
+    }
+}