PAT 1144 The Missing Number (20 分)

#include <iostream>
#include <map>
using namespace std;
int main() {
    int n, a, num = 0;
    cin >> n;
    map<int, int> m;
    for (int i = 0; i < n; i++) {
        cin >> a;
        m[a]++;
    }
    while(++num)
        if (m[num] == 0) break;
    cout << num;
    return 0;
}

#include <iostream>
#include <vector>
using namespace std;
int main() {
    int n,temp;
    cin >> n;
    vector<int>a(100005,0);
    for(int i=0;i<n;i++){
        scanf("%d",&temp);
        if(temp>0&&temp<100005)a[temp]=1;
    }
    for(int i=1;i<100005;i++){
        if(a[i]==0) {
            cout<<i;
            break;
        }
    }
    return 0;
}