diff --git a/test003.cpp b/test003.cpp
new file mode 100644
index 0000000..e4c64ca
--- /dev/null
+++ b/test003.cpp
@@ -0,0 +1,21 @@
+class Solution {
+public:
+    int longestConsecutive(vector<int>& nums) {
+        unordered_map <int, int> data;
+        for(int x:nums) data[x] = 1;
+        int res = 0;
+        for(auto &n:data){
+            if(n.second){
+                int val = n.first; int len = 1;
+                for(int i = 1; data.count(val - i)&&data[val - i]; i++){
+                    data[val - i] = 0; len++;
+                }
+                for(int i = 1; data.count(val + i)&&data[val + i]; i++){
+                    data[val + i] = 0; len++;
+                }
+                res = max(len, res);
+            }
+        }
+        return res;
+    }
+};
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