small_integer_array

// from codility demo.
#include <iostream>
#include <vector>
#include <algorithm>
#include <set>

using namespace std;
/*
    my algo: 
        discard negatives below 1.
        have min, max, max-min = range,
        sort,
        make hashmap array? reduce duplicates.
        check if #'s in range (from array)
        if no gap, max + 1 
        else return gap
*/

int solution(vector<int> &A) {
    
    vector<int> B = A; // copy 

    int size = A.size(), gap=0;
    int max, min, range; // postive only
    //sort for calculations
    sort(B.begin(), B.end()); 
    //  for (int i = 0; i < size; i++) cout << B[i] << " ";   cout << endl;
    // get max/min!
    max = *max_element(B.begin(), B.end());
    min = *min_element(B.begin(), B.end());
    std::cout << "max: " << max << " min: " << min << endl; 
    
    set <int> s;
    set <int>::iterator it;
    
    for (int x : B) { // take away duplicates
        s.insert(x);
    }
    
    int flag = 0;
    // if negative , case where all array is negative? 
    for (it = s.begin(); it != s.end(); it++){
        if (*it < 0) {
            gap=1;
            
            return gap; //default to 1 
        }
    }
    
    for (int j = 1; j < max; j++) {
    
        if (s.find(j) == s.end()) {
            gap = j-1; // no gap
        }
        else {
            gap = max;
        }
        
    }
    cout << "gap: " << gap << endl;
    return gap+1; 
}

int main() {
    
    vector <int> A = {1,2,3}; //->4, A=[-1,3] -> 1, A = [1,2,1,3,4,6] -> 5
    
    int c = solution(A);
    
    cout << "sol: " <<  c << endl;
    
    return 0;
}