无脑蛮力

#include <iostream>
#include <vector>using namespace::std;
using std::cout;
using std::cin; int main() 
{int num;vector<int> nums;while(cin >> num){nums.push_back(num);if(getchar()=='\n') {break;}}int t,n=nums.size();for(int i=0; i<n-1; i++){for(int j=i+1; j<n; j++){if(nums[i] > nums[j]){t=nums[i];nums[i]=nums[j];nums[j]=t;}}}t=-1;for(int i=0; i<=n; i++){t++;if(nums[i] != t){i=n;}}std::cout << t;return 0;  
}