題解：寫了簡單題，好開心，我果然不適合學算法.......寫寫簡單題，當個鹹魚就好了嘛！！

#include <iostream>
#include <algorithm>
#include <cstdlib>
#include <cstdio>
#include <cstring>
#include <sstream>
using namespace std;

const int maxn = 100000 + 50;
int N;
int num[maxn];

void solve()
{
    
 
int cnt = 0;
    string line;
    int a;
    getchar();
    for (int i = 0; i < N; i++)
    {
        getline(cin, line);
        istringstream in(line);
        while (in >> a) {
            num[cnt++] = a;
        }
    }
    sort(num, num + cnt);
    
    int m = 0, n = 0;
    
 
int flag_m = 0, flag_n = 0;
    for (int i = 0; i < cnt - 1; i++) {
        if (num[i + 1] - num[i] > 1 && !flag_m) {
            m = num[i] + 1; 
            flag_m = 1;
        }
        if ((num[i] == num[i + 1]) && !flag_n) {
            n = num[i];
            flag_n 
 
= 1; 
        }
        if (flag_m && flag_n) {
            break;
        }
    }
    printf("%d %d\n", m, n);
}

int main()
{
    cin >> N;
    solve();
    return 0;
}

第四屆藍橋杯第七題 錯誤票據