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Aug 5, 2023usama
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Daily: Cutting a Wall

Dec 20, 2021aedrarian

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/*
Good morning! Here's your coding interview problem for today.
This problem was asked by LinkedIn.
A wall consists of several rows of bricks of various integer lengths and uniform height. Your goal is to find a vertical line going from the top to the bottom of the wall that cuts through the fewest number of bricks. If the line goes through the edge between two bricks, this does not count as a cut.
For example, suppose the input is as follows, where values in each row represent the lengths of bricks in that row:
[[3, 5, 1, 1],
[2, 3, 3, 2],
[5, 5],
[4, 4, 2],
[1, 3, 3, 3],
[1, 1, 6, 1, 1]]
The best we can we do here is to draw a line after the eighth brick, which will only require cutting through the bricks in the third and fifth row.
Given an input consisting of brick lengths for each row such as the one above, return the fewest number of bricks that must be cut to create a vertical line.
AUTHORS NOTE:
Makes following assumptions:
- Each row is same length
- Data is in file called "data.dat" and formatted in space-separated rows
- The cuts at the beginning and end of the wall are not solutions
This requires the following file named data.dat that is a space separated file, or similar formatted file:
----START FILE----
3 5 1 1
2 3 3 2
5 5
4 4 2
1 3 3 3
1 1 6 1 1
----END FILE----
*/
#include <algorithm>
#include <iostream>
#include <fstream>
#include <map>
#include <sstream>
#include <string>
#include <vector>
using namespace std;
int main()
{
vector<vector<int>> wall;
ifstream in;
in.open("data.dat");
if(!in.good())
{
cout << "ERROR: File failed to open properly.\n";
}
/* Get input from space separated file */
string line;
while(!in.eof())
{
getline(in, line);
int i;
vector<int> currv;
stringstream strs(line);
while(strs >> i)
currv.push_back(i);
wall.push_back(currv);
}
/* Convert each value from "length of brick" to "position at end of brick" */
for(int y = 0; y < wall.size(); y++)
{
wall.at(y).pop_back(); //Delet last val
for(int x = 1; x < wall.at(y).size(); x++) //Skip the first bc data doesn't need change
wall.at(y).at(x) += wall.at(y).at(x-1);
}
/* Check output. COMMENT OUT */
// for(auto row : wall)
// {
// for(int pos : row)
// cout << pos << " ";
// cout << endl;
// }
/* Determine which ending position is most common, and cut there */
//Exclude final position, which will be the size of the wall
int mode = -1;
int amt = -1;
vector<int> tried;
for(auto row : wall)
{
for(int pos : row) //For each pos in the wall
{
//Guard. If pos is contained in the list, skip pos
if(find(tried.begin(), tried.end(), pos) != tried.end())
continue;
tried.push_back(pos);
/* Cycle through each row to see if it contains the pos */
int curramt = 0;
for(auto currrow : wall)
{
if( find( currrow.begin(), currrow.end(), pos ) != currrow.end() )
curramt++;
}
//cout << pos << " " << curramt << endl;
if(curramt > amt)
{
amt = curramt;
mode = pos;
}
}
}
cout << "Please cut at position " << mode << endl;
cout << "This will cut through " << (wall.size() - amt) << " bricks." << endl;
return 0;
}

Command line game

Nov 19, 2022CodeCatch

0 likes • 1 view

#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;
}

Heapify a vector

Nov 19, 2022CodeCatch

0 likes • 0 views

#include <iostream>
#include <vector>
using namespace std;
void swap(int *a, int *b)
{
int temp = *b;
*b = *a;
*a = temp;
}
void heapify(vector<int> &hT, int i)
{
int size = hT.size();
int largest = i;
int l = 2 * i + 1;
int r = 2 * i + 2;
if (l < size && hT[l] > hT[largest])
largest = l;
if (r < size && hT[r] > hT[largest])
largest = r;
if (largest != i)
{
swap(&hT[i], &hT[largest]);
heapify(hT, largest);
}
}
void insert(vector<int> &hT, int newNum)
{
int size = hT.size();
if (size == 0)
{
hT.push_back(newNum);
}
else
{
hT.push_back(newNum);
for (int i = size / 2 - 1; i >= 0; i--)
{
heapify(hT, i);
}
}
}
void deleteNode(vector<int> &hT, int num)
{
int size = hT.size();
int i;
for (i = 0; i < size; i++)
{
if (num == hT[i])
break;
}
swap(&hT[i], &hT[size - 1]);
hT.pop_back();
for (int i = size / 2 - 1; i >= 0; i--)
{
heapify(hT, i);
}
}
void printArray(vector<int> &hT)
{
for (int i = 0; i < hT.size(); ++i)
cout << hT[i] << " ";
cout << "\n";
}
int main()
{
vector<int> heapTree;
insert(heapTree, 3);
insert(heapTree, 4);
insert(heapTree, 9);
insert(heapTree, 5);
insert(heapTree, 2);
cout << "Max-Heap array: ";
printArray(heapTree);
deleteNode(heapTree, 4);
cout << "After deleting an element: ";
printArray(heapTree);
}

C++ Scanner

Jul 16, 2024LeifMessinger

0 likes • 10 views

//===============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;
}

2D Array Chessboard Pattern

Nov 18, 2022AustinLeath

0 likes • 14 views

#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;
}

Literal Bruh

Jul 30, 2023LeifMessinger

1 like • 5 views

//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;
}