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Daily: Cutting a Wall

0 likes • Dec 20, 2021
C++
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BFS/DFS/TopSort

rlbishop99
0 likes • Apr 30, 2021
C++
#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.
}
}
}

Daily: Find missing array value

aedrarian
0 likes • Dec 24, 2021
C++
/*
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;
}

Heapify a vector

CodeCatch
0 likes • Nov 19, 2022
C++
#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);
}

Hello, World!

AustinLeath
0 likes • Nov 18, 2022
C++
#include <iostream>
using namespace std;
int main()
{
cout << "Hello, World!" << endl;
return 0;
}

CSCE 1040 Lab 9

AustinLeath
0 likes • Nov 18, 2022
C++
#include <iostream>
#include "PlaylistNode.h"
using namespace std;
void PrintMenu(string title);
int main() {
string plTitle;
cout << "Enter playlist's title:" << endl;
getline(cin, plTitle);
PrintMenu(plTitle);
return 0;
}
void PrintMenu(string title) {
Playlist list;
string id;
string sname;
string aname;
int length;
int oldPos;
int newPos;
char choice;
while(true) {
cout << endl << title << " PLAYLIST MENU" << endl;
cout << "a - Add song" << endl;
cout << "d - Remove song" << endl;
cout << "c - Change position of song" << endl;
cout << "s - Output songs by specific artist" << endl;
cout << "t - Output total time of playlist (in seconds)" << endl;
cout << "o - Output full playlist" << endl;
cout << "q - Quit" << endl << endl;
cout << "Choose an option:" << endl;
cin >> choice;
cin.ignore();
if (choice == 'q') {
exit(1);
}
else if (choice == 'a') {
cout << "\nADD SONG" << endl;
cout << "Enter song's unique ID: ";
cin >> id;
cin.ignore();
cout << "Enter song's name: ";
getline(cin,sname);
cout << "Enter artist's name: ";
getline(cin,aname);
cout << "Enter song's length (in seconds): ";
cin >> length;
list.AddSong(id, sname, aname, length);
}
else if (choice == 'd') {
cout << "\nREMOVE SONG" << endl;
cout << "Enter song's unique ID: ";
cin >> id;
list.RemoveSong(id);
}
else if (choice == 'c') {
cout << "\nCHANGE POSITION OF SONG" << endl;
cout << "Enter song's current position: ";
cin >> oldPos;
cout << "Enter new position for song: ";
cin >> newPos;
list.ChangePosition(oldPos, newPos);
}
else if (choice == 's') {
cout << "\nOUTPUT SONGS BY SPECIFIC ARTIST" << endl;
cout << "Enter artist's name: ";
getline(cin, aname);
list.SongsByArtist(aname);
}
else if (choice == 't') {
cout << "\nOUTPUT TOTAL TIME OF PLAYLIST (IN SECONDS)" << endl;
cout << "Total time: " << list.TotalTime() << " seconds" << endl;
}
else if (choice == 'o') {
cout << endl << title << " - OUTPUT FULL PLAYLIST" << endl;
list.PrintList();
}
else {
cout << "Invalid menu choice! Please try again." << endl;
}
}
}

Command line game

CodeCatch
0 likes • Nov 19, 2022
C++
#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;
}