add 287

Author: rustykitty

0287-find-the-duplicate-numer.cpp

@@ -0,0 +1,20 @@
+/*
+287. Find the Duplicate Number
+
+Submitted: January 5, 2024
+
+Runtime: 63 ms (beats 20.20%)
+Memory: 87.86 MB (beats 15.89%)
+*/
+
+class Solution {
+public:
+    int findDuplicate(vector<int>& nums) {
+        unordered_map<int, int> map;
+        for (const int n : nums) {
+            map[n]++;
+            if (map[n] == 2) return n;
+        }
+        return 0;
+    }
+};