#include <iostream>
using namespace std;

int main {
   cout << 1; 
}

#include <iostream>
using namespace std;

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

/*
Algorithm:
Step 1: Get radius of the cylinder from the user and store in variable r
Step 2: Get height of the cylinder from the user and store in variable h
Step 3: Multiply radius * radius * height * pi and store in v
Step 4: Display the volume
*/

#include <iostream>
using namespace std;


int main()
{
        float r; //define variable for radius
        float h; //define variable for height
        float v;
        float pi;
        pi=3.1416;

        cout<<"Enter radius:";
        cin>>r;

        cout<<"Enter height:";
        cin>>h;

        v=r*r*h*pi;  //compute volume

        cout<<"Radius:"<<r<<"\tHeight:"<<h<<endl; //display radius and height

        cout<<"\n************************\n";

        cout<<"Volume:"<<v<<endl;//display volume

        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; 
}

/*
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 <string>
#include <iostream>
#include "PlaylistNode.h"
using namespace std;

PlaylistNode::PlaylistNode() {
   uniqueID = "none";
   songName = "none";
   artistName = "none";
   songLength = 0;
   nextNodePtr = 0;
}

PlaylistNode::PlaylistNode(string uniqueID_, string songName_, string artistName_, int songLength_) {
   uniqueID = uniqueID_;
   songName = songName_;
   artistName = artistName_;
   songLength = songLength_;
   nextNodePtr = 0;
}

void PlaylistNode::InsertAfter(PlaylistNode* ptr) {
   this->SetNext(ptr->GetNext());
   ptr->SetNext(this);
}

void PlaylistNode::SetNext(PlaylistNode* ptr) {
   nextNodePtr = ptr;
}

string PlaylistNode::GetID() {
   return uniqueID;
}

string PlaylistNode::GetSongName() {
   return songName;
}

string PlaylistNode::GetArtistName() {
   return artistName;
}

int PlaylistNode::GetSongLength() {
   return songLength;
}

PlaylistNode* PlaylistNode::GetNext() {
   return nextNodePtr;
}

void PlaylistNode::PrintPlaylistNode() {
   cout << "Unique ID: " << uniqueID << endl;
   cout << "Song Name: " << songName << endl;
   cout << "Artist Name: " << artistName << endl;
   cout << "Song Length (in seconds): " << songLength << endl;
}

Playlist::Playlist() {
   head = tail = 0;
}

void Playlist::AddSong(string id, string songname, string artistname, int length) {
   PlaylistNode* n = new PlaylistNode(id, songname, artistname, length);
   if (head == 0) {
      head = tail = n;
   }
   else {
      n->InsertAfter(tail);
      tail = n;
   }
}

bool Playlist::RemoveSong(string id) {
   if (head == NULL) {
      cout << "Playlist is empty" << endl;
      return false;
   }
   
   PlaylistNode* curr = head;
   PlaylistNode* prev = NULL;
   while (curr != NULL) {
      if (curr->GetID() == id) {
         break;
      }
      prev = curr;
      curr = curr->GetNext();
   }
   
   if (curr == NULL) {
      cout << "\"" << curr->GetSongName() << "\" is not found" << endl;
      return false;
   }
   else {
      if (prev != NULL) {
         prev ->SetNext(curr->GetNext());
      }
      else {
         head = curr->GetNext();
      }
      if (tail == curr) {
         tail = prev;
      }
      cout << "\"" << curr->GetSongName() << "\" removed." << endl;
      delete curr;
      return true;
   }
}

bool Playlist::ChangePosition(int oldPos, int newPos) {
   if (head == NULL) {
      cout << "Playlist is empty" << endl;
      return false;
   }
   
   PlaylistNode* prev = NULL;
   PlaylistNode* curr = head;
   
   int pos;
   if (head == NULL || head == tail) {
      return false;
   }
   
   for (pos = 1; curr != NULL && pos < oldPos; pos++) {
      prev = curr;
      curr = curr->GetNext();
   }
   if (curr != NULL) {
      string currentSong = curr->GetSongName();
      
      if (prev == NULL) {
         head = curr->GetNext();
      }
      else {
         prev->SetNext(curr->GetNext());
      }
      if (curr == tail) {
         tail = prev;
      }
      
      PlaylistNode* curr1 = curr;
      prev = NULL;
      curr = head;
      for (pos = 1; curr != NULL && pos < newPos; pos++) {
         prev = curr;
         curr = curr->GetNext();
      }
      if (prev == NULL) {
         curr1->SetNext(head);
         head = curr1;
      }
      else {
         curr1->InsertAfter(prev);
      }
      if (curr == NULL) {
         tail = curr1;
      }
      cout << "\"" << currentSong << "\" moved to position " << newPos << endl;
      return true;
   }
   else {
      cout << "Song's current position is invalid" << endl;
      return false;
   }
}

void Playlist::SongsByArtist(string artist) {
   if (head == NULL) {
      cout << "Playlist is empty" << endl;
   }
   else {
      PlaylistNode* curr = head;
      int i = 1;
      while (curr != NULL) {
         if (curr->GetArtistName() == artist) {
            cout << endl << i << "." << endl;
            curr->PrintPlaylistNode();
         }
         curr = curr->GetNext();
         i++;
      }
   }
}

int Playlist::TotalTime() {
   int total = 0;
   PlaylistNode* curr = head;
   
   while (curr != NULL) {
      total += curr->GetSongLength();
      curr = curr->GetNext();
   }
   return total;
}

void Playlist::PrintList() {
   if (head == NULL) {
      cout << "Playlist is empty" << endl;
   }
   else {
      PlaylistNode* curr = head;
      int i = 1;
      while (curr != NULL) {
         cout << endl << i++ << "." << endl;
         curr->PrintPlaylistNode();
         curr = curr->GetNext();
      }
   }
}