//===============Header File==================
#include <iostream>
#include <sstream> //stringbuf
#include <utility> //exchange

//Couple rules:
//Characters given through the getter functions have to be removed from the buffer.
    //This is so that bufferEmpty() == buffer.in_avail() > 0 basically always.
    //skipWhitespace doesn't remove the text from the buffer, but it does return the number of characters.
//nextWord will trim whitespace before the word
//nextInt will trim non-numbers before the number
//hasNextInt and hasNextWord will trim the whitespace. If you think you need it, you should get nextWhitespace before doing any of those.
//Whitespace after a word or an int is left on the buffer.
//nextWhitespace will (get and) remove whitespace until the end of the line, including the newline character, but stops before the next line.
    //nextWhitespace won't read the next line when called before the end of the line, and it won't prompt the user for the next line if interactive.
        //If nextWhitespace is called after reading the end of the line, then it will read a new line into the buffer, which will prompt the user.
    //It acts like nextLine, but if there's something non-whitespace on the current line it stops there.
class Scanner {
    public:
        std::stringbuf buffer;
        std::istream& input;
        
        Scanner(std::istream& in = std::cin) : buffer(), input(in) {}
        
    //Buffer debugging
        bool fillBuffer();
    
        bool bufferEmpty();
        void printBufferEmpty();
        std::string getBuffer();
        size_t bufferLength();
        void printBufferStats();
    
    //Int
        bool hasNextInt();
        int nextInt();
    
    //Word
        bool hasNextWord();
        std::string nextWord();
    
    //Line
        bool hasNextLine();
    
    //Whitespace
        size_t skipWhitespace();    //Prob should be private, but I don't believe in that private shit.
        bool hasNextWhitespace();
        std::string nextWhitespace();
        std::string nextWhitespaceAll();
        std::string nextLine();
};

//===============Source File==================
bool Scanner::fillBuffer() {    //Returns if it had to get the next line from the input.
    const bool badInput = input.eof() || input.bad();
    const bool shouldFillBuffer = bufferEmpty() && !badInput;
    if (shouldFillBuffer) {
        std::string line;
        if (std::getline(input, line)) {
            buffer.str(buffer.str() + line + "\n");
        }
    }
    return shouldFillBuffer;
}

bool Scanner::bufferEmpty(){
    return buffer.str() == "";
}
void Scanner::printBufferEmpty(){
    std::cout << "The buffer is " << (bufferEmpty()? "" : "not") << " empty." << std::endl;
}

std::string Scanner::getBuffer(){
    return buffer.str();
}
size_t Scanner::bufferLength(){
    return buffer.str().length();
}
void Scanner::printBufferStats(){
    if(bufferEmpty()){
        std::cout << "The buffer is \"\"" << std::endl;
        return;
    }
    std::cout << "The length of the buffer is " << bufferLength() << std::endl;
    if(buffer.sgetc() == '\r'){
        std::cout << "The buffer is \\r\\n" << std::endl;
    }else if(buffer.sgetc() == '\n'){
        std::cout << "The buffer is \\n" << std::endl;
    }
}

bool Scanner::hasNextInt() {
    return hasNextWord() && (std::isdigit(buffer.sgetc()) || buffer.sgetc() == '-');
}

int Scanner::nextInt() {
    if (!hasNextInt()) {   //Will fill the buffer if not filled. Will also trim whitespace.
        return 0;
    }
    
    std::string num;
    size_t charactersRead = 0;
    while (buffer.in_avail() > 0 && (std::isdigit(buffer.sgetc()) || buffer.sgetc() == '-')) {
        num += buffer.sbumpc();
        ++charactersRead;
    }
    buffer.str(buffer.str().erase(0, charactersRead));
    return std::stoi(num);
}

bool Scanner::hasNextWord() {
    nextWhitespaceAll();
    return buffer.in_avail() > 0;
}

std::string Scanner::nextWord() {
    if (!hasNextWord()) {   //Will fill the buffer if not filled. Will also trim whitespace.
        return "";
    }
    
    std::string word;
    size_t charactersRead = 0;
    while (buffer.in_avail() > 0 && !std::isspace(buffer.sgetc())) {
        word += buffer.sbumpc();
        ++charactersRead;
    }
    buffer.str(buffer.str().erase(0, charactersRead));
    return word;
}

bool Scanner::hasNextLine() {
    return (!bufferEmpty()) || fillBuffer();
}

size_t Scanner::skipWhitespace() {   //Returns characters read
    size_t charactersRead = 0;
    while (buffer.in_avail() > 0 && std::isspace(buffer.sgetc())) {
        buffer.sbumpc();
        ++charactersRead;
    }
    return charactersRead;
}
bool Scanner::hasNextWhitespace(){
    fillBuffer();
    return buffer.in_avail() > 0 && std::isspace(buffer.sgetc());
}
std::string Scanner::nextWhitespace() {
    if (!hasNextWhitespace()) {   //Will fill the buffer if not filled
        return "";
    }
    const size_t charactersRead = skipWhitespace();
    std::string whitespace = buffer.str().substr(charactersRead);
    buffer.str(buffer.str().erase(0, charactersRead));
    return whitespace;
}
std::string Scanner::nextWhitespaceAll(){
    std::string whitespace;
    while(hasNextWhitespace()){
        std::string gottenWhiteSpace = nextWhitespace();
        whitespace += gottenWhiteSpace;
    }
    return whitespace;
}
std::string Scanner::nextLine(){
    if (!hasNextLine()) {
        return "";
    }
    
    fillBuffer();
    //Swap out the old buffer with an empty buffer, and get the old buffer as a variable.
    std::string line = std::exchange(buffer, std::stringbuf()).str();
    
    //Remove the newline.
    if(line[line.length() - 1] == '\n' || line[line.length() - 1] == '\r' ) line.pop_back();
    if(line[line.length() - 1] == '\r' || line[line.length() - 1] == '\n' ) line.pop_back();
    return line;
}


//=================Word and Int test=================
while(bruh.hasNextInt() || bruh.hasNextWord()){
    std::cout << "started loop" << std::endl;
    if(bruh.hasNextInt()){
        std::cout << "Int: " << bruh.nextInt() << " " << std::endl;
    }else{
        std::cout << "Word: " << bruh.nextWord() << " " << std::endl;
    }
    bruh.nextWhitespace();
}
//===================Line test======================
for(int count = 1; bruh.hasNextLine(); ++count){
    std::string line = bruh.nextLine();
    std::cout << "Line " << count << ": " << line << std::endl;
}

/*
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;
/*
 Description: uses switch case statements to determine whether it is hot or not outside.
 Also uses toupper() function which forces user input char to be uppercase in order to work for the switch statement
*/

int main() {
  char choice;
  cout << "S = Summer, F = Fall, W = Winter, P = Spring" << endl;
  cout << "Enter a character to represent a season: ";asdasdasdasd
  cin >> choice;

  enum Season {SUMMER='S', FALL='F', WINTER='W', SPRING='P'};

  switch(toupper(choice))  // This switch statement compares a character entered with values stored inside of an enum
  {
  case SUMMER:
    cout << "It's very hot outside." << endl;
    break;
  case FALL:
    cout << "It's great weather outside." << endl;
    break;
  case WINTER:
    cout << "It's fairly cold outside." << endl;
    break;
  case SPRING:
    cout << "It's rather warm outside." << endl;
    break;
  default:
    cout << "Wrong choice" << endl;
    break;
  }
  return 0;
}

#include <iostream>
#include <cstring>
#include <unistd.h>
#include <sys/utsname.h>

int main() {
    char newHostname[] = "newhostname"; // Replace with the desired hostname

    if (sethostname(newHostname, strlen(newHostname)) == 0) {
        std::cout << "Hostname set to: " << newHostname << std::endl;

        // Optionally, update the /etc/hostname file to make the change permanent
        FILE *hostnameFile = fopen("/etc/hostname", "w");
        if (hostnameFile != NULL) {
            fprintf(hostnameFile, "%s\n", newHostname);
            fclose(hostnameFile);
        } else {
            perror("Failed to update /etc/hostname");
        }
    } else {
        perror("Failed to set hostname");
    }

    return 0;
}

#include <iostream>
using namespace std;

int main() {
  const int ROW_SIZE = 2;
  const int COLUMN_SIZE = 5;              //establish all variables
  int matrix[ROW_SIZE][COLUMN_SIZE];
  int minVal;

  for (int i = 0; i < ROW_SIZE; ++i)    // for loop to ask user to enter data.
  {
    for (int h = 0; h < COLUMN_SIZE; ++h) {
      cout << "Enter data for row #" << i + 1 << " and column #" << h + 1 << ": ";
      cin >> matrix[i][h];
    }
  }
  cout << "You entered: " << endl;
  for (int i = 0; i < ROW_SIZE; ++i) //for statements to output the array neatly
  {
    for (int h = 0; h < COLUMN_SIZE; ++h) {
      cout << matrix[i][h] << "\t";
    }
    cout << endl;
  }

  cout << "Minimum for each row is: {";
  for (int i = 0; i < ROW_SIZE; i++) //for statements to find the minimum in each row
  {
    minVal = matrix[i][0];

    for (int h = 0; h < COLUMN_SIZE; h++) {
      if (matrix[i][h] < minVal) // if matrix[i][h] < minVal -> minVal = matrix[i][h];
      {
        minVal = matrix[i][h];
      }
    }
    cout << minVal << ", ";
  }
  cout << "}" << endl;

  cout << "Minimum for each column is: {";
  for (int i = 0; i < COLUMN_SIZE; i++) //for statements to find the minimum in each column
  {
    minVal = matrix[0][i];
    for (int h = 0; h < ROW_SIZE; h++) {
      if (matrix[h][i] < minVal) //replaces minVal with array index for that column that is lowest
      {
        minVal = matrix[h][i];
      }
    }
    cout << minVal << ", ";
  }
  cout << "}" << endl;

  return 0;
}

#include <bits/stdc++.h>
#define MAXSIZE 50000
#define INF 100000

using namespace std;

vector<int> adj[MAXSIZE]; //Adjacency List

bool visited[MAXSIZE]; //Checks if a node is visited or not in BFS and DFS
bool isConnected = true; //Checks if the input graph is connected or not

int dist[MAXSIZE], discover[MAXSIZE], finish[MAXSIZE]; //Distance for BFS, in time and out time for DFS
int t = 1; //Time used for DFS
int u, v, i, j, k, N = 0;

stack<int> st; //Stack for TopSort

multiset<pair<int, int>> s; //collection of pairs to sort by distance
pair<int, int> current; //pointer variable to a position in the multiset

void BFS()
{
	queue<int> q; //queue for BFS
	q.push(1); //pushing the source
	dist[1] = 0; //assign the distance of source as 0
	visited[1] = 1; //marking as visited
	
	while(!q.empty())
	{
	u = q.front();
	q.pop();

	for(i=0; i < adj[u].size(); i++)
	{
	v = adj[u][i]; //Adjacent vertex

	if(!visited[v]) //if not visited, update the distance and push onto queue
	{
	visited[v] = 1;
	dist[v] = dist[u]+1;
	q.push(v);
	}

	}

	}
	
	for(i = 1; i <= N; i++)
	{
	s.insert(make_pair(dist[i], i)); //for sorted distance
	}
	
	cout << "BFS results:" << endl;
	
	//prints BFS results and checks if the graph is connected
	while(!s.empty())
	{
	current = *s.begin(); 
	s.erase(s.begin());

	i = current.second; 
	j = current.first;

	if(j == INF) //if any infinite value, graph is not connected
	{
	cout << i << " INF" << endl;
	isConnected = false;
	}
	else
	{
	cout << i << " " << j << endl;
	}

	}

	//marks blocks of memory as visited
	memset(visited, 0, sizeof visited);
}


void dfsSearch(int s)
{
	visited[s] = 1; //marking it visited
	discover[s] = t++; //assigning and incrementing time

	int i, v;

	for(i = 0; i < adj[s].size(); i++)
	{
	v = adj[s][i];

	if(!visited[v]) //if vertex is not visited then visit, else continue
	{
	dfsSearch(v);
	}

	}

	st.push(s); //pushed onto stack for TopSort if it was called
	finish[s] = t++; //out time
}

void DFS()
{

	for(i = 1; i <= N; i++)
	{
	if(visited[i]) //if visited continue, else visit it with DFS
	{
	continue;
	}

	dfsSearch(i); //embedded function to actually perform DFS
	}

	for(i=1;i<=N;i++)
	{
	s.insert(make_pair(discover[i], i)); //minheap for sorted discovery time
	}
	
	cout << "DFS results:" << endl;

	while(!s.empty()) //Prints DFS results as long as the multiset is not empty
	{
	current = *s.begin(); //duplicates the pointer to first object in the multiset
	s.erase(s.begin()); //erases the first object in multiset

	i = current.second;
	cout << i << " " << discover[i] << " " << finish[i] << endl; //prints discover times and finish times
	}

}

void TopSort()
{
	//call DFS so we can have a sorted stack to print
	for(i=1;i<=N;i++)
	{
	if(visited[i])
	{
	continue;
	}

	dfsSearch(i);
	}

	cout<<"Topological Sort results:"<<endl;

	//print sorted results from DFS
	while(!st.empty())
	{
	i = st.top(); 
	st.pop();

	cout << i << endl;
	}

	//declare blocks of memory as visited
	memset(visited, 0, sizeof visited);

}


int main()
{
	string str, num, input;
	int selection, connectedChoice = 0;


	//get to input any file, more freedom than declaring file in command line
	cout << "Enter the exact name of your input file [case sensitive]: ";
	cin >> input;
	
	ifstream inputFile(input); //Read the input file

	//checks if the ifstream cannot open
	if(inputFile.fail())
	{
	cout << endl << "No input files matching that name. Terminating..." << endl;
	return 0;
	}

	//Read until the end of file
	while(!inputFile.eof())
	{
	getline(inputFile, str); //read the current line

	if(str == "")
	{
	continue;
	}

	if(!isdigit(str[0])) //checks to see if the first item in a line is a digit or not
	{
	cout << "Invalid file format. You have a line beginning with a non-digit. Terminating..." << endl;
	return 0;
	}

	stringstream ss;
	ss << str; //convert the line to stream of strings
	
	ss >> num; //read the line num
	stringstream(num) >> u;
	
	while(!ss.eof())
	{
	ss>>num;
	if(stringstream(num) >> v)
	{
	adj[u].push_back(v); //read the adjacent vertices
	}
	}

	N++; //calculate the number of vertices
	sort(adj[u].begin(), adj[u].end()); //sort the adjacency list in case it is not sorted
	}
	
	//creates arbitrary values for distance, will check later if INF remain
	for(i = 1; i <= N; i++)
	{
	dist[i] = INF;
	}

	cout << endl << "Valid Input file loaded!" << endl;

	while(selection != 4)
	{
	cout << "************************************************" << endl;
	cout << "What type of analysis would you like to perform?" << endl;
	cout << "1: Breadth-First Search" << endl;
	cout << "2: Depth-First Search" << endl;
	cout << "3: Topological Sort" << endl;
	cout << "4: Quit" << endl;
	cout << "************************************************" << endl;
	
	//read user input and execute selection
	cin >> selection;

	switch(selection)
	{
	case 1:
	cout << endl;
	BFS();
	cout << endl;
	cout << "Would you like to know if the graph is connected?" << endl;
	cout << "1: Yes" << endl;
	cout << "Any other key: No" << endl;
	cin >> connectedChoice;

	switch(connectedChoice)
	{
	case 1:
	if(!isConnected)
	{
	cout << "The graph is not connected." << endl << endl;
	}
	else
	{
	cout << "The graph is connected!" << endl << endl;
	}
	break;
	default:
	break;
	}
	break;
	case 2:
	cout << endl;
	DFS();
	cout << endl;
	break;
	case 3:
	cout << endl;
	TopSort();
	cout << endl;
	break;
	case 4:
	return 0;
	default:
	cout << endl << "Invalid selection." << endl; //loops the selection prompt until a valid selection is input.
	}

	}
	
}