题解 | #序列找数#

#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

int main() {
    int a, b;
    vector<int> v;

    while (cin >> a ) { 
        for (int i=0;i<a;i++) {
            cin>>b;
            v.push_back(b);
        }
        sort(v.begin(),v.end());
         for (int i=0;i<a;i++) {
            if(v[i]!=i){
                cout << i  << endl;
                break;
            }
            
        }
        
    }
}