/*
Good morning! Here's your coding interview problem for today.

This problem was asked by Stripe.

Given an array of integers, find the first missing positive integer in linear time and constant space. In other words, find the lowest positive integer that does not exist in the array. The array can contain duplicates and negative numbers as well.

For example, the input [3, 4, -1, 1] should give 2. The input [1, 2, 0] should give 3.

You can modify the input array in-place.
*/
#include <iostream>
using namespace std;

int calcMissing(int* input, int size)
{
	int sum = 0;
	int n = 1; //add one to account for missing value
	for(int i = 0; i < size; i++)
	{
	if(input[i] > 0)
	{
	sum += input[i];
	n++;
	}
	}

	//If no numbers higher than 0, answer is 1
	if(sum == 0)
	return 1;

	return (n*(n+1)/2) - sum; //Formula is expectedSum - actualSum
	/* expectedSum = n*(n+1)/2, the formula for sum(1, n) */
}

int main()
{

	cout << calcMissing(new int[4]{3, 4, -1, 1}, 4) << endl;
	cout << calcMissing(new int[3]{1, 2, 0}, 3) << endl;

	//No positive numbers
	cout << calcMissing(new int[1]{0}, 1) << endl;
}

#include <iostream>
using namespace std;

int main()
{
    cout << "Hello, World!" << endl;
    return 0;
}

int main()

#include <iostream>
using namespace std;

/* Function: get_coeff
Parameters: double& coeff, int pos passed from bb_4ac
Return: type is void so no return, but does ask for user to input data that establishes what a b and c are.
*/
void get_coeff(double& coeff, int pos) {
  char position;
  if(pos == 1) {
    position = 'a';
  } else if(pos == 2) {   //a simple system to determine what coefficient the program is asking for.
    position = 'b';
  } else {
    position = 'c';
  }
  cout << "Enter the co-efficient " << position << ":"; //prompt to input coeff
  coeff = 5; //input coeff
}

/* Function: bb_4ac
Parameters: no parameters passed from main, but 3 params established in function, double a, b, c.
Return: b * b - 4 * a * c
*/
double bb_4ac() {
  double a, b, c; //coefficients of a quadratic equation
  get_coeff(a, 1); // call function 1st time
  get_coeff(b, 2); // call function 2nd time
  get_coeff(c, 3); // call function 3rd time
  return b * b - 4 * a * c; //return b * b - 4 * a * c
}

int main() {
  cout << "Function to calculate the discriminant of the equation. . . " << endl;
  double determinate = bb_4ac(); //assign double determinate to bb_4ac function
  cout << "The discriminant for given values is: " << determinate << endl;  //output the determinate!
}

#include <iostream>
using namespace std;

int main() {

cout << "Hello World!\n";
// Prints out "Hello World"
return 0;

}

//Leif Messinger
//Compile with C++ 20
#include <iostream>
#include <ranges>
#include <vector>
#include <functional>
#include <cctype> //toupper
#include <cxxabi.h>

template <typename T>
void printType(){
    std::cout << abi::__cxa_demangle(typeid(T).name(), NULL, NULL, NULL) << std::endl;
}

template <typename T>
class Slicer{
    public:
        T begin_;
        T end_;
        T trueEnd;
        Slicer(T begin, T end): begin_(begin), end_(begin), trueEnd(end){}
        template<typename U>
        Slicer(U&& vec) : begin_(vec.begin()), end_(vec.begin()), trueEnd(vec.end()){}
        Slicer& finish(){
            begin_ = end_;
            end_ = trueEnd;
            return (*this);
        }
        Slicer& to(long int index){
            begin_ = end_;
            if(index > 0){
                end_ = (begin_ + index);
            }else{
                index *= -1;
                end_ = (trueEnd - index);
            }
            return (*this);
        }
        Slicer& operator[](long int index){
            return to(index);
        }
        T begin(){
            return this->begin_;
        }
        T end(){
            return this->end_;
        }
        Slicer& operator()(std::function<void(decltype(*begin_))> func) {
            for(decltype(*begin_) thing : (*this)){
                func(thing);
            }
            return (*this);
        }
};
static_assert(std::ranges::range< Slicer<std::vector<int>::const_iterator> >);

int main(){
    std::string vec = "abcdefghijklmnopqrstuvwxyz";
    Slicer<std::string::const_iterator> bruh(vec);
    
    //printType<decltype(bruh)>();

    bruh.to(3)([](char yeet){
        std::cout << yeet;
    })
    .to(-1)([](char yeet){
        std::cout << char(std::toupper(yeet));
    }).finish()([](char yeet){
        std::cout << yeet << yeet << yeet << yeet << yeet;
    });
    
    std::cout << std::endl << std::endl;
    
    int arr[] = {1, 2, 3, 4, 5, 6, 7, 8};
    Slicer<int*> arrSlicer(arr, arr + (sizeof(arr)/sizeof(int)));
    
    std::cout << "[";
    arrSlicer.to(-1)([](int yeet){
        std::cout << yeet << ", ";
    }).finish()([](int yeet){
        std::cout << yeet << "]" << std::endl;
    });

    return 0;
}