heozeop: missing number

Author: heozeop

missing-number/heozeop.cpp

@@ -0,0 +1,19 @@
+// time complexity: O(n)
+// spatial complexity: O(n)
+
+class Solution {
+public:
+    int missingNumber(vector<int>& nums) {
+        set<int> exisingNums(nums.begin(), nums.end());
+
+        int answer = -1;
+        for(int i = 0; i <= nums.size(); ++i) {
+            if(exisingNums.find(i) == exisingNums.end()) {
+                answer = i;
+                break;
+            }
+        }
+
+        return answer;
+    }
+};