PAT甲级——A1144 TheMissingNumber【20】

Given N integers, you are supposed to find the smallest positive integer that is NOT in the given list.

Input Specification:

Each input file contains one test case. For each case, the first line gives a positive integer N (≤). Then N integers are given in the next line, separated by spaces. All the numbers are in the range of int.

Output Specification:

Print in a line the smallest positive integer that is missing from the input list.

Sample Input:

10
5 -25 9 6 1 3 4 2 5 17

Sample Output:

7

Solution:

　　水题，没得意思

　　两种方法，用map存储后查找即可

　　另一种方法就是排序后从1查找即可

#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
int main()
{
    int n, x, res = 1;
    vector<int>v;
    cin >> n;
    while (n--)
    {
        cin >> x;
        if (x > 0)
            v.push_back(x);
    }
    sort(v.begin(), v.end());
    for (auto a : v)
        if (a == res)
            res++;
    cout << res;
    return 0;
}