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Daily: Find missing array value

Dec 24, 2021aedrarian
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C++ Range Slicer

Oct 31, 2023LeifMessinger

0 likes • 3 views

//Leif Messinger
//Compile with C++ 20
#include <iostream>
#include <ranges>
#include <vector>
#include <functional>
#include <cctype> //toupper
#include <cxxabi.h>
template <typename T>
void printType(){
std::cout << abi::__cxa_demangle(typeid(T).name(), NULL, NULL, NULL) << std::endl;
}
template <typename T>
class Slicer{
public:
T begin_;
T end_;
T trueEnd;
Slicer(T begin, T end): begin_(begin), end_(begin), trueEnd(end){}
template<typename U>
Slicer(U&& vec) : begin_(vec.begin()), end_(vec.begin()), trueEnd(vec.end()){}
Slicer& finish(){
begin_ = end_;
end_ = trueEnd;
return (*this);
}
Slicer& to(long int index){
begin_ = end_;
if(index > 0){
end_ = (begin_ + index);
}else{
index *= -1;
end_ = (trueEnd - index);
}
return (*this);
}
Slicer& operator[](long int index){
return to(index);
}
T begin(){
return this->begin_;
}
T end(){
return this->end_;
}
Slicer& operator()(std::function<void(decltype(*begin_))> func) {
for(decltype(*begin_) thing : (*this)){
func(thing);
}
return (*this);
}
};
static_assert(std::ranges::range< Slicer<std::vector<int>::const_iterator> >);
int main(){
std::string vec = "abcdefghijklmnopqrstuvwxyz";
Slicer<std::string::const_iterator> bruh(vec);
//printType<decltype(bruh)>();
bruh.to(3)([](char yeet){
std::cout << yeet;
})
.to(-1)([](char yeet){
std::cout << char(std::toupper(yeet));
}).finish()([](char yeet){
std::cout << yeet << yeet << yeet << yeet << yeet;
});
std::cout << std::endl << std::endl;
int arr[] = {1, 2, 3, 4, 5, 6, 7, 8};
Slicer<int*> arrSlicer(arr, arr + (sizeof(arr)/sizeof(int)));
std::cout << "[";
arrSlicer.to(-1)([](int yeet){
std::cout << yeet << ", ";
}).finish()([](int yeet){
std::cout << yeet << "]" << std::endl;
});
return 0;
}

Test

Jun 17, 2024oceantran27

0 likes • 2 views

#include <iostream>
using namespace std;
int main {
cout << 1;
}

Hash Table Example

Nov 18, 2022AustinLeath

0 likes • 0 views

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;
}

Hello World!

Aug 31, 2020joshwrou

1 like • 2 views

#include <iostream>
using namespace std;
int main() {
cout << "Hello World!\n";
// Prints out "Hello World"
return 0;
}

Egg Problem Template

Jul 10, 2023LeifMessinger

0 likes • 4 views

#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;
}

Infection Simulation

Nov 18, 2022AustinLeath

0 likes • 2 views

/*
this program will simulate the spreading of a disease through a
grid of people, starting from a user-defined person. It will count
the number of turns taken before everyone on the grid is immunized
to the disease after having caught it once.
This program will user the SIR model (Susceptible, Infectious, Recovered)
and cellular automata to simulate the people in the grid.
*/
#include <iostream>
using namespace std;
/* Any and all global variables */
const int SIZE = 8; //Size of the square person array
/* Any and all functions */
void gridDefaultify(char[][SIZE], int);
//Purpose: Sets each item in the person array to 's'
//Parameters: A square, two-dimensional array
// The size of that array's bounds
void gridDisplay(char[][SIZE], int);
//Purpose: Formats and prints the information in the person grid
//Parameters: A square, two-dimensional array
// The value of the current day
void nextTurn(char[][SIZE], char[][SIZE], int&);
//Purpose: Updates the grid of people, and the current day
//Parameters: Two square, two-dimensional arrays
// A reference to the current day (so that it can be updated)
int countInfected(char[][SIZE], int);
//Purpose: Counts the number of infectious people on the grid
//Parameters: A square, two-dimensional array
// The size of that array's bounds
int main(){
int currentDay = 0; //Infection begins on day 0, and ends one day after the last person is Recovered
char gridCurrent[SIZE][SIZE]; //Grid of all people
char gridUpdate[SIZE][SIZE]; //Where the user chooses to start the infection
int xToInfect;
int yToInfect; //Set of coordinates for the initial infection position, given by user
//Initializes the grids to all 's'
gridDefaultify(gridCurrent, SIZE);
gridDefaultify(gridUpdate, SIZE);
//The below block gets the initial infection coordinates from the user
cout << "Please enter a location to infect: ";
while(true){
cin >> xToInfect >> yToInfect;
xToInfect--;
yToInfect--;
if(xToInfect < 0 || yToInfect < 0 || xToInfect >= SIZE || yToInfect >= SIZE){
cout << "Those coordinates are outside the bounds of this region." << endl;
cout << "Please enter another location to infect: ";
continue;
} else {
gridCurrent[xToInfect][yToInfect] = 'i';
break;
}
}
//Displays the initial state of the grid
gridDisplay(gridCurrent, currentDay);
//The below block will display and update the grid until the infection is done.
while(true){
nextTurn(gridCurrent, gridUpdate, currentDay);
gridDisplay(gridCurrent, currentDay);
if(countInfected(gridCurrent, SIZE) == 0) break; //Once there are no more infected, the game is done
}
//Displays the number of days taken for the infection to end
cout << "It took " << currentDay + 1 << " days for the outbreak to end";
cout << endl;
return 0;
}
void gridDefaultify(char arr[][SIZE], int arrSize){
for(int x = 0; x < arrSize; x++){
for(int y = 0; y < arrSize; y++){
arr[x][y] = 's'; //Sets all items in the passed-in array to 's'
}
}
return;
}
void gridDisplay(char arr[][SIZE], int day){
cout << "Day " << day << endl; //Prints the current day
for(int x = 0; x < SIZE; x++){
for(int y = 0; y < SIZE; y++){
cout << arr[x][y] <<" "; //Prints the array's contents
}
cout << endl; //Formats with newlines
}
cout << endl; //Some spacing
return;
}
void nextTurn(char today[][SIZE], char update[][SIZE], int& day){
day++; //Updates the day
int xCheck; //X coordinate to be checked
int yCheck; //Y coordinate to be checked
for(int x = 0; x < SIZE; x++){
for(int y = 0; y < SIZE; y++){
//Sets all 'i' to 'r' in the new grid
if(today[x][y] == 'i' || today[x][y] == 'r'){
update[x][y] = 'r'; //Updates all infectious to recovered, and keeps current recovered
}
if(today[x][y] == 's'){ // If the person is susceptible...
for(int xCheck = x-1; xCheck <= x+1; xCheck++){ // Check all x coordinates around the person
for(int yCheck = y-1; yCheck <= y+1; yCheck++){ // Check all y coordinates around the person
if(xCheck == x && yCheck == y){
// Don't check at the person because there is no need to check there
} else {
if(xCheck >= 0 && yCheck >= 0 && xCheck < SIZE && yCheck < SIZE){ // Make sure the checked coordinates are in bounds
if(today[xCheck][yCheck] == 'i'){ //Is the person at the checked coordinates infected?
update[x][y] = 'i'; //If so, update the 's' to 'i' in the new grid
}
}
}
}
}
}
}
}
for(int x = 0; x < SIZE; x++){
for(int y = 0; y < SIZE; y++){
today[x][y] = update[x][y]; //Updates today's grid with the new values
}
}
}
int countInfected(char arr[][SIZE], int arrSize){
int count = 0;
for(int x = 0; x < arrSize; x++){
for(int y = 0; y < arrSize; y++){
if(arr[x][y] == 'i') count++; //Increments count for each infected person in the grid
}
}
return count;
}