68. 0到n-1中缺失的数字

https://www.acwing.com/problem/content/submission/code_detail/7757230/

AcWing/68/68.cpp

@@ -0,0 +1,13 @@
+class Solution {
+  public:
+    int getMissingNumber(vector<int>& nums) {
+        set<int> s;
+        for (int i = 0; i <= nums.size(); i++) {
+            s.insert(i);
+        }
+        for (int i : nums) {
+            s.erase(i);
+        }
+        return *s.begin();
+    }
+};