stringstream

#include<bits/stdc++.h>
//#include<sstream>
using namespace std;
const int N=1e4+10;
int a[N];
int cnt=0;
int main()
{
    int n;
    int num;
    cin>>n;
    string s;
    getline(cin,s);
    while(n--){
        getline(cin,s);
       // stringstream ss;
        //ss<<s;
        stringstream ss(s);
        while(ss>>num){
            a[cnt++]=num;   
        }
    }
    sort(a,a+cnt);
    int res1,res2;
    for(int i=1;i<cnt;i++){
        if(a[i]==a[i-1])
            res2=a[i];
        else if(a[i]>=a[i-1]+2){
            res1=a[i]-1;
        }
    }
    cout<<res1<<' '<<res2<<endl;
    return 0;
}

方法二 遇到’\n’ break

#include<bits/stdc++.h>
using namespace std;
const int N = 1e5 + 10;
int a[N];
int minn=2e9, maxx=-2e9;
int main()
{
    int n;
    cin >> n;
    int x;
    while (n--) {
        char c;
        while (1) {
            cin >> x;
            char c = getchar();
            a[x]++;
            minn = min(minn,x);
            maxx = max(maxx, x);
            if (c == '\n')
                break;
        }
    }
    int num1, num2=0;
    for (int i = minn; i <= maxx; i++) {
        if (a[i] == 0)
            num1 = i;
        if (a[i] > 1)
            num2 = i;

    }
    cout << num1 <<' '<< num2 << endl;
    return 0;
}