#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>
using namespace std;

const int rows = 8;
const int cols = 8;
char chessboard[rows][cols];

void setBoard(char chessboard[][cols]);
void printBoard(char chessboard[][cols]);

void setBoard(char chessboard[][cols]) {
    for(int i = 0; i < rows; i++) {
        for(int j = 0; j < cols; j++) {
            if(i % 2 == 0 && j % 2 == 0) {
                chessboard[i][j] = 'x';
            } else {
                if(i % 2 != 0 && j % 2 == 1) {
                    chessboard[i][j] = 'x';
                } else {
                    chessboard[i][j] = '-';
                }
            }
        }
    }
    return;
}

void printBoard(char chessboard[][cols]) {
    for(int i = 0; i < rows; i++) {
        for(int j = 0; j < cols; j++) {
            cout << chessboard[i][j] << " ";
        }
        cout << endl;
    }
    return;
}

int main(int argc, char const *argv[])
{
    setBoard(chessboard);
    printBoard(chessboard);
    return 0;
}

#include "stdio.h"
#include <stdlib.h>

int main (int argCount, char** args) {
    int a = atoi(args[1]);
    int b = atoi(args[2]);

    unsigned int sum = 0;

    unsigned int p = 1;
    for (unsigned int i = 1; i < b; i++) {
        p = p * i;
    }

    // (b!, (1 + b)!, (2 + b)!, ..., (n + b)!)
    for (unsigned int i = 0; i < a; i++) {
        p = p * (i + b);
        sum = sum + p;
    }
    printf("y: %u\n", sum);
    return 0;
}

#include <iostream>
#include <fstream>
#include <string>
#include <cstring>

using namespace std;

//This program makes a new text file that contains all combinations of two letters.
// aa, ab, ..., zy, zz

int main(){
	string filename = "two_letters.txt";

	ofstream outFile;
	outFile.open(filename.c_str());

	if(!outFile.is_open()){
		cout << "Something's wrong. Closing..." << endl;
		return 0;
	}

	for(char first = 'a'; first <= 'z'; first++){
		for(char second = 'a'; second <= 'z'; second++){
			outFile << first << second << " ";
		}
		outFile << endl;
	}

	return 0;
}

using namespace std; 
  
class Hash 
{ 
    int BUCKET;    // No. of buckets 
  
    // Pointer to an array containing buckets 
    list<int> *table; 
public: 
    Hash(int V);  // Constructor 
  
    // inserts a key into hash table 
    void insertItem(int x); 
  
    // deletes a key from hash table 
    void deleteItem(int key); 
  
    // hash function to map values to key 
    int hashFunction(int x) { 
        return (x % BUCKET); 
    } 
  
    void displayHash(); 
}; 
  
Hash::Hash(int b) 
{ 
    this->BUCKET = b; 
    table = new list<int>[BUCKET]; 
} 
  
void Hash::insertItem(int key) 
{ 
    int index = hashFunction(key); 
    table[index].push_back(key);  
} 
  
void Hash::deleteItem(int key) 
{ 
  // get the hash index of key 
  int index = hashFunction(key); 
  
  // find the key in (inex)th list 
  list <int> :: iterator i; 
  for (i = table[index].begin(); 
           i != table[index].end(); i++) { 
    if (*i == key) 
      break; 
  } 
  
  // if key is found in hash table, remove it 
  if (i != table[index].end()) 
    table[index].erase(i); 
} 
  
// function to display hash table 
void Hash::displayHash() { 
  for (int i = 0; i < BUCKET; i++) { 
    cout << i; 
    for (auto x : table[i]) 
      cout << " --> " << x; 
    cout << endl; 
  } 
} 
  
// Driver program  
int main() 
{ 
  // array that contains keys to be mapped 
  int a[] = {15, 11, 27, 8, 12}; 
  int n = sizeof(a)/sizeof(a[0]); 
  
  // insert the keys into the hash table 
  Hash h(7);   // 7 is count of buckets in 
               // hash table 
  for (int i = 0; i < n; i++)  
    h.insertItem(a[i]);   
  
  // delete 12 from hash table 
  h.deleteItem(12); 
  
  // display the Hash table 
  h.displayHash(); 
  
  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.
	}

	}
	
}