//Constant prefix notation solver using bruh
//Could make it infix or postfix later
#include<string>
#include<vector>
#include<iostream>

std::vector<long double> bruhBuff;

long double operator ""bruh(long double a){
    bruhBuff.push_back(a);
    return a;
}

long double operator ""bruh(const char op){
    if(bruhBuff.size() < 2) throw "Bruh weak";
    
    long double b = bruhBuff.back();
    bruhBuff.pop_back();
    long double a = bruhBuff.back();
    bruhBuff.pop_back();
    
    
    switch(op){
        case (int)('+'):
            return a + b;
        case (int)('-'):
            return a - b;
        case (int)('*'):
            return a * b;
        case (int)('/'):
            return a / b;
    }
    return 69l;
}
 
int main(){
    1.0bruh;
    2.0bruh;
    std::cout << '+'bruh << std::endl;
    
    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;
}

#include <iostream>
#include <cstring>
int main(int argc, char** argv){
	//With decimal
	if(strstr(argv[1], ".") != nullptr){
		int i = 0;
		//Skip i to first non 0 digit
		while(argv[1][i] < '1' || argv[1][i] > '9') ++i;
		//If digit comes before decimal
		if((argv[1] + i) < strstr(argv[1], ".")){	//Good example of pointer arithmetic
			std::cout << strlen(argv[1] + i) - 1 << std::endl;	//Another good example
		}else{
			//If digit is after decimal
			std::cout << strlen(argv[1] + i) << std::endl;
		}
	}else{
	//Without decimal
		int m = 0;
		int i = 0;
		while(argv[1][i] < '1' || argv[1][i] > '9') ++i;	//In case of some number like 0045
		for(; argv[1][i] != '\0'; ++i){
			if(argv[1][i] >= '1' && argv[1][i] <= '9') m = i + 1;
		}
		std::cout << m << std::endl;
	}
	return 0;
}

#include <iostream>
#include <vector>
#include <utility>
#include <algorithm>
#include <chrono>
using namespace std;

#include <stdio.h>
#include <Windows.h>

int nScreenWidth = 120;			// Console Screen Size X (columns)
int nScreenHeight = 40;			// Console Screen Size Y (rows)
int nMapWidth = 16;				// World Dimensions
int nMapHeight = 16;

float fPlayerX = 14.7f;			// Player Start Position
float fPlayerY = 5.09f;
float fPlayerA = 0.0f;			// Player Start Rotation
float fFOV = 3.14159f / 4.0f;	// Field of View
float fDepth = 16.0f;			// Maximum rendering distance
float fSpeed = 5.0f;			// Walking Speed

int main()
{
	// Create Screen Buffer
	wchar_t *screen = new wchar_t[nScreenWidth*nScreenHeight];
	HANDLE hConsole = CreateConsoleScreenBuffer(GENERIC_READ | GENERIC_WRITE, 0, NULL, CONSOLE_TEXTMODE_BUFFER, NULL);
	SetConsoleActiveScreenBuffer(hConsole);
	DWORD dwBytesWritten = 0;

	// Create Map of world space # = wall block, . = space
	wstring map;
	map += L"#########.......";
	map += L"#...............";
	map += L"#.......########";
	map += L"#..............#";
	map += L"#......##......#";
	map += L"#......##......#";
	map += L"#..............#";
	map += L"###............#";
	map += L"##.............#";
	map += L"#......####..###";
	map += L"#......#.......#";
	map += L"#......#.......#";
	map += L"#..............#";
	map += L"#......#########";
	map += L"#..............#";
	map += L"################";

	auto tp1 = chrono::system_clock::now();
	auto tp2 = chrono::system_clock::now();
	
	while (1)
	{
		// We'll need time differential per frame to calculate modification
		// to movement speeds, to ensure consistant movement, as ray-tracing
		// is non-deterministic
		tp2 = chrono::system_clock::now();
		chrono::duration<float> elapsedTime = tp2 - tp1;
		tp1 = tp2;
		float fElapsedTime = elapsedTime.count();


		// Handle CCW Rotation
		if (GetAsyncKeyState((unsigned short)'A') & 0x8000)
			fPlayerA -= (fSpeed * 0.75f) * fElapsedTime;

		// Handle CW Rotation
		if (GetAsyncKeyState((unsigned short)'D') & 0x8000)
			fPlayerA += (fSpeed * 0.75f) * fElapsedTime;
		
		// Handle Forwards movement & collision
		if (GetAsyncKeyState((unsigned short)'W') & 0x8000)
		{
			fPlayerX += sinf(fPlayerA) * fSpeed * fElapsedTime;;
			fPlayerY += cosf(fPlayerA) * fSpeed * fElapsedTime;;
			if (map.c_str()[(int)fPlayerX * nMapWidth + (int)fPlayerY] == '#')
			{
				fPlayerX -= sinf(fPlayerA) * fSpeed * fElapsedTime;;
				fPlayerY -= cosf(fPlayerA) * fSpeed * fElapsedTime;;
			}			
		}

		// Handle backwards movement & collision
		if (GetAsyncKeyState((unsigned short)'S') & 0x8000)
		{
			fPlayerX -= sinf(fPlayerA) * fSpeed * fElapsedTime;;
			fPlayerY -= cosf(fPlayerA) * fSpeed * fElapsedTime;;
			if (map.c_str()[(int)fPlayerX * nMapWidth + (int)fPlayerY] == '#')
			{
				fPlayerX += sinf(fPlayerA) * fSpeed * fElapsedTime;;
				fPlayerY += cosf(fPlayerA) * fSpeed * fElapsedTime;;
			}
		}

		for (int x = 0; x < nScreenWidth; x++)
		{
			// For each column, calculate the projected ray angle into world space
			float fRayAngle = (fPlayerA - fFOV/2.0f) + ((float)x / (float)nScreenWidth) * fFOV;

			// Find distance to wall
			float fStepSize = 0.1f;		  // Increment size for ray casting, decrease to increase										
			float fDistanceToWall = 0.0f; //                                      resolution

			bool bHitWall = false;		// Set when ray hits wall block
			bool bBoundary = false;		// Set when ray hits boundary between two wall blocks

			float fEyeX = sinf(fRayAngle); // Unit vector for ray in player space
			float fEyeY = cosf(fRayAngle);

			// Incrementally cast ray from player, along ray angle, testing for 
			// intersection with a block
			while (!bHitWall && fDistanceToWall < fDepth)
			{
				fDistanceToWall += fStepSize;
				int nTestX = (int)(fPlayerX + fEyeX * fDistanceToWall);
				int nTestY = (int)(fPlayerY + fEyeY * fDistanceToWall);
				
				// Test if ray is out of bounds
				if (nTestX < 0 || nTestX >= nMapWidth || nTestY < 0 || nTestY >= nMapHeight)
				{
					bHitWall = true;			// Just set distance to maximum depth
					fDistanceToWall = fDepth;
				}
				else
				{
					// Ray is inbounds so test to see if the ray cell is a wall block
					if (map.c_str()[nTestX * nMapWidth + nTestY] == '#')
					{
						// Ray has hit wall
						bHitWall = true;

						// To highlight tile boundaries, cast a ray from each corner
						// of the tile, to the player. The more coincident this ray
						// is to the rendering ray, the closer we are to a tile 
						// boundary, which we'll shade to add detail to the walls
						vector<pair<float, float>> p;

						// Test each corner of hit tile, storing the distance from
						// the player, and the calculated dot product of the two rays
						for (int tx = 0; tx < 2; tx++)
							for (int ty = 0; ty < 2; ty++)
							{
								// Angle of corner to eye
								float vy = (float)nTestY + ty - fPlayerY;
								float vx = (float)nTestX + tx - fPlayerX;
								float d = sqrt(vx*vx + vy*vy); 
								float dot = (fEyeX * vx / d) + (fEyeY * vy / d);
								p.push_back(make_pair(d, dot));
							}

						// Sort Pairs from closest to farthest
						sort(p.begin(), p.end(), [](const pair<float, float> &left, const pair<float, float> &right) {return left.first < right.first; });
						
						// First two/three are closest (we will never see all four)
						float fBound = 0.01;
						if (acos(p.at(0).second) < fBound) bBoundary = true;
						if (acos(p.at(1).second) < fBound) bBoundary = true;
						if (acos(p.at(2).second) < fBound) bBoundary = true;
					}
				}
			}
		
			// Calculate distance to ceiling and floor
			int nCeiling = (float)(nScreenHeight/2.0) - nScreenHeight / ((float)fDistanceToWall);
			int nFloor = nScreenHeight - nCeiling;

			// Shader walls based on distance
			short nShade = ' ';
			if (fDistanceToWall <= fDepth / 4.0f)			nShade = 0x2588;	// Very close	
			else if (fDistanceToWall < fDepth / 3.0f)		nShade = 0x2593;
			else if (fDistanceToWall < fDepth / 2.0f)		nShade = 0x2592;
			else if (fDistanceToWall < fDepth)				nShade = 0x2591;
			else											nShade = ' ';		// Too far away

			if (bBoundary)		nShade = ' '; // Black it out
			
			for (int y = 0; y < nScreenHeight; y++)
			{
				// Each Row
				if(y <= nCeiling)
					screen[y*nScreenWidth + x] = ' ';
				else if(y > nCeiling && y <= nFloor)
					screen[y*nScreenWidth + x] = nShade;
				else // Floor
				{				
					// Shade floor based on distance
					float b = 1.0f - (((float)y -nScreenHeight/2.0f) / ((float)nScreenHeight / 2.0f));
					if (b < 0.25)		nShade = '#';
					else if (b < 0.5)	nShade = 'x';
					else if (b < 0.75)	nShade = '.';
					else if (b < 0.9)	nShade = '-';
					else				nShade = ' ';
					screen[y*nScreenWidth + x] = nShade;
				}
			}
		}

		// Display Stats
		swprintf_s(screen, 40, L"X=%3.2f, Y=%3.2f, A=%3.2f FPS=%3.2f ", fPlayerX, fPlayerY, fPlayerA, 1.0f/fElapsedTime);

		// Display Map
		for (int nx = 0; nx < nMapWidth; nx++)
			for (int ny = 0; ny < nMapWidth; ny++)
			{
				screen[(ny+1)*nScreenWidth + nx] = map[ny * nMapWidth + nx];
			}
		screen[((int)fPlayerX+1) * nScreenWidth + (int)fPlayerY] = 'P';

		// Display Frame
		screen[nScreenWidth * nScreenHeight - 1] = '\0';
		WriteConsoleOutputCharacter(hConsole, screen, nScreenWidth * nScreenHeight, { 0,0 }, &dwBytesWritten);
	}

	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 <iostream>
#include <vector>
#include <limits>

#define DEBUG_TRIAL false

class Trial{
    public:
        const size_t HEIGHT;
        std::string record;
        
        //Breaking height is the index of the floor, so 0 is the bottom floor, height-1 is the top floor.
        //Eggs is the eggs remaining.
        //Start is the bottom floor.
        //End is one above the top floor.
        const size_t BREAKING_HEIGHT;
        size_t eggs;
        size_t start;
        size_t end;
        
        
        size_t floorsLeft(){
            return (end-start);
        }
        
        size_t middle(){
            return start + (floorsLeft()/2UL);
        }
        
        size_t drops = 0;
        Trial(const size_t BREAKING_HEIGHT, size_t eggs, size_t start, size_t end): BREAKING_HEIGHT(BREAKING_HEIGHT), eggs(eggs), start(start), end(end), HEIGHT(end), record(end, '_'){
            record[BREAKING_HEIGHT] = 'B'; //Marking the breaking point
        }
        
        bool foundAnswer(){
            return ((record[0] == 'X') || (record.find("OX")!=std::string::npos));
        }
        
        //returns true if the egg broke.
        //height is the index of the floor, so 0 is the bottom floor, height-1 is the top floor.
        bool drop(size_t height){
            
            #if DEBUG_TRIAL
                std::cout << "Start: " << start << ". End: " << end << ". Floors Left: " << floorsLeft() << ". Middle Index: " << middle() << std::endl;
            #endif
            
            drops++;
            bool cracked = height >= BREAKING_HEIGHT;
            if(cracked) --eggs;
            
            //Update the record
            record[height] = (height >= BREAKING_HEIGHT)? 'X' : 'O';
            
            #if DEBUG_TRIAL
                //Print the record
                std::cout << record << std::endl;
            #endif
        
            return cracked;
        }
        
        size_t nowWhat(){
            if(foundAnswer()){
                return drops;
            }else if(eggs <= 0){ //Ran out of eggs
                throw "Algorithm failed! No more eggs!";
                return 1UL;
            }else if(eggs > 1){
                return wrecklessSearch();
            }else{
                return safeSearch();
            }
        }
        
        size_t safeSearch(){
            if(drop(start)){
                --end;
            }else{
                ++start;
            }
            
            return nowWhat();
        }
        
        size_t wrecklessSearch(){
            //If the egg breaks
            if(drop(middle())){
                end -= (floorsLeft()/2UL);
            }else{ //egg doesn't crack
                start += (floorsLeft()/2UL);
            }
            
            return nowWhat();
        }
        
        //returns the amount of drops needed to find the answer
        size_t search(){
            return nowWhat();
        }
};

//Height is the height of the building in floors.
//Breaking height is the index of the floor, so 0 is the bottom floor, height-1 is the top floor.
//Eggs is the eggs given.
//returns the amount of drops needed to find the answer
size_t search(const size_t height, const size_t BREAKING_HEIGHT, size_t eggs){
    Trial trial(BREAKING_HEIGHT, eggs, 0, height);
    return trial.search();
}

class TrialStats {
    public:
        size_t min = std::numeric_limits<size_t>::max();
        size_t max = 0;
        double mean = -1.0;
        
        void printStats(){
            // Print the results
            std::cout << "Minimum drops: " << min << std::endl;
            std::cout << "Maximum drops: " << max << std::endl;
            std::cout << "Mean drops: " << mean << std::endl;
        }
};

//Benchmarks all the possible breaking points of a single building height with a number of eggs.
TrialStats trial(const size_t HEIGHT, const size_t eggs){
    
    TrialStats stats;
    int totaldrops = 0;

    //Test every possible breaking point
    //Breaking height is the index of the floor, so 0 is the bottom floor, height-1 is the top floor.
    for (int breakingHeight = 0; breakingHeight < HEIGHT; ++breakingHeight) {
        size_t drops = search(HEIGHT, breakingHeight, eggs);

        stats.min = std::min(stats.min, drops);
        stats.max = std::max(stats.max, drops);
        totaldrops += drops;
    }

    // Calculate the mean number of drops
    stats.mean = static_cast<double>(totaldrops) / HEIGHT;
    
    return stats;
}

//Benchmarks a single building height from 1 egg to MAX_EGGS
void testTower(const size_t height, const size_t MAX_EGGS){
    //Drop every amount of eggs that you'd need.
    for (int eggs = 1; eggs <= MAX_EGGS; ++eggs) {
        std::cout << "Building height: " << height << ". Num eggs: " << eggs << std::endl;
        
        TrialStats stats = trial(height, eggs);
        stats.printStats();
        
        std::cout << std::endl << std::endl;
    }
}

//Benchmarks all buildings from 0 to MAX_HEIGHT
void benchmark(const size_t MAX_HEIGHT){
    const size_t MAX_EGGS = 2;
    //Test every building
    for (size_t height = 1; height <= MAX_HEIGHT; ++height) {
        testTower(height, std::min(height, MAX_EGGS));
    }
}

int main() {
    constexpr size_t MAX_HEIGHT = 36;
    
    benchmark(MAX_HEIGHT);

    return 0;
}