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minimum matrix values

0 likes • Nov 18, 2022
C++
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Two Letter Combinations

AustinLeath
0 likes • Nov 18, 2022
C++
#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;
}

Stock Options Analyzer

AustinLeath
0 likes • Nov 18, 2022
C++
#include <iostream>
#include <cmath>
#include <string.h>
using namespace std;
int main() {
string tickerName;
int numOfContracts;
float currentOptionValue;
cout << "Enter a stock ticker: ";
getline(cin, tickerName);
cout << "Enter the current number of " << tickerName << " contracts you are holding: ";
cin >> numOfContracts;
cout << "Enter the current price of the option: ";
cin >> currentOptionValue;
cout << "The value of your " << tickerName << " options are: $" << (currentOptionValue * 100.00) * (numOfContracts);
cout << endl;
return 0;
}

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;
}

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.
}
}
}

wordScore.cpp

ThiccDaddyLOAF
0 likes • Apr 16, 2023
C++
#include <iostream>
#include <string> //Should already be in iostream
#include <cstdlib>
//A word score adds up the character values. a-z gets mapped to 1-26 for the values of the characters.
//wordScore [wordValue]
//Pipe in the input into stdin, or type the words yourself.
//Lowercase words only
int characterValue(const char b){
return ((b >= 'a') && (b <= 'z'))? ((b - 'a') + 1) : 0;
}
int main(int argc, char** argv){
//The first argument specifies if you are trying to look for a certain word score
int wordValue = (argc > 1)? std::atoi(argv[1]) : 0;
std::string line;
while(std::getline(std::cin, line)){
int sum = 0;
for(const char c : line){
sum += characterValue(c);
}
if(wordValue){ //If wordValue is 0 or the sum is the correct value
if(wordValue == sum){
std::cout << line << std::endl;
}
} else {
std::cout << sum << "\t" << line << std::endl;
}
}
return 0;
}

Audio Frequency Amplitudes

ThiccDaddyLOAF
0 likes • Aug 27, 2021
C++
//From https://create.arduino.cc/projecthub/abhilashpatel121/easyfft-fast-fourier-transform-fft-for-arduino-9d2677
#include <cmath>
#include <iostream>
const unsigned char sine_data[] = { //Quarter a sine wave
0,
4, 9, 13, 18, 22, 27, 31, 35, 40, 44,
49, 53, 57, 62, 66, 70, 75, 79, 83, 87,
91, 96, 100, 104, 108, 112, 116, 120, 124, 127,
131, 135, 139, 143, 146, 150, 153, 157, 160, 164,
167, 171, 174, 177, 180, 183, 186, 189, 192, 195, //Paste this at top of program
198, 201, 204, 206, 209, 211, 214, 216, 219, 221,
223, 225, 227, 229, 231, 233, 235, 236, 238, 240,
241, 243, 244, 245, 246, 247, 248, 249, 250, 251,
252, 253, 253, 254, 254, 254, 255, 255, 255, 255
};
float sine(int i){ //Inefficient sine
int j=i;
float out;
while(j < 0) j = j + 360;
while(j > 360) j = j - 360;
if(j > -1 && j < 91) out = sine_data[j];
else if(j > 90 && j < 181) out = sine_data[180 - j];
else if(j > 180 && j < 271) out = -sine_data[j - 180];
else if(j > 270 && j < 361) out = -sine_data[360 - j];
return (out / 255);
}
float cosine(int i){ //Inefficient cosine
int j = i;
float out;
while(j < 0) j = j + 360;
while(j > 360) j = j - 360;
if(j > -1 && j < 91) out = sine_data[90 - j];
else if(j > 90 && j < 181) out = -sine_data[j - 90];
else if(j > 180 && j < 271) out = -sine_data[270 - j];
else if(j > 270 && j < 361) out = sine_data[j - 270];
return (out / 255);
}
//Example data:
//-----------------------------FFT Function----------------------------------------------//
float* FFT(int in[],unsigned int N,float Frequency){ //Result is highest frequencies in order of loudness. Needs to be deleted.
/*
Code to perform FFT on arduino,
setup:
paste sine_data [91] at top of program [global variable], paste FFT function at end of program
Term:
1. in[] : Data array,
2. N : Number of sample (recommended sample size 2,4,8,16,32,64,128...)
3. Frequency: sampling frequency required as input (Hz)
If sample size is not in power of 2 it will be clipped to lower side of number.
i.e, for 150 number of samples, code will consider first 128 sample, remaining sample will be omitted.
For Arduino nano, FFT of more than 128 sample not possible due to mamory limitation (64 recomended)
For higher Number of sample may arise Mamory related issue,
Code by ABHILASH
Documentation:https://www.instructables.com/member/abhilash_patel/instructables/
2/3/2021: change data type of N from float to int for >=256 samples
*/
unsigned int sampleRates[13]={1,2,4,8,16,32,64,128,256,512,1024,2048};
int a = N;
int o;
for(int i=0;i<12;i++){ //Snapping N to a sample rate in sampleRates
if(sampleRates[i]<=a){
o = i;
}
}
int in_ps[sampleRates[o]] = {}; //input for sequencing
float out_r[sampleRates[o]] = {}; //real part of transform
float out_im[sampleRates[o]] = {}; //imaginory part of transform
int x = 0;
int c1;
int f;
for(int b=0;b<o;b++){ // bit reversal
c1 = sampleRates[b];
f = sampleRates[o] / (c1 + c1);
for(int j = 0;j < c1;j++){
x = x + 1;
in_ps[x]=in_ps[j]+f;
}
}
for(int i=0;i<sampleRates[o];i++){ // update input array as per bit reverse order
if(in_ps[i]<a){
out_r[i]=in[in_ps[i]];
}
if(in_ps[i]>a){
out_r[i]=in[in_ps[i]-a];
}
}
int i10,i11,n1;
float e,c,s,tr,ti;
for(int i=0;i<o;i++){ //fft
i10 = sampleRates[i]; // overall values of sine/cosine :
i11 = sampleRates[o] / sampleRates[i+1]; // loop with similar sine cosine:
e = 360 / sampleRates[i+1];
e = 0 - e;
n1 = 0;
for(int j=0;j<i10;j++){
c=cosine(e*j);
s=sine(e*j);
n1=j;
for(int k=0;k<i11;k++){
tr = c*out_r[i10 + n1]-s*out_im[i10 + n1];
ti = s*out_r[i10 + n1]+c*out_im[i10 + n1];
out_r[n1 + i10] = out_r[n1]-tr;
out_r[n1] = out_r[n1]+tr;
out_im[n1 + i10] = out_im[n1]-ti;
out_im[n1] = out_im[n1]+ti;
n1 = n1+i10+i10;
}
}
}
/*
for(int i=0;i<sampleRates[o];i++)
{
std::cout << (out_r[i]);
std::cout << ("\t"); // un comment to print RAW o/p
std::cout << (out_im[i]); std::cout << ("i");
std::cout << std::endl;
}
*/
//---> here onward out_r contains amplitude and our_in conntains frequency (Hz)
for(int i=0;i<sampleRates[o-1];i++){ // getting amplitude from compex number
out_r[i] = sqrt(out_r[i]*out_r[i]+out_im[i]*out_im[i]); // to increase the speed delete sqrt
out_im[i] = i * Frequency / N;
std::cout << (out_im[i]); std::cout << ("Hz");
std::cout << ("\t"); // un comment to print freuency bin
std::cout << (out_r[i]);
std::cout << std::endl;
}
x = 0; // peak detection
for(int i=1;i<sampleRates[o-1]-1;i++){
if(out_r[i]>out_r[i-1] && out_r[i]>out_r[i+1]){
in_ps[x] = i; //in_ps array used for storage of peak number
x = x + 1;
}
}
s = 0;
c = 0;
for(int i=0;i<x;i++){ // re arraange as per magnitude
for(int j=c;j<x;j++){
if(out_r[in_ps[i]]<out_r[in_ps[j]]){
s=in_ps[i];
in_ps[i]=in_ps[j];
in_ps[j]=s;
}
}
c=c+1;
}
float* f_peaks = new float[sampleRates[o]];
for(int i=0;i<5;i++){ // updating f_peak array (global variable)with descending order
f_peaks[i]=out_im[in_ps[i]];
}
return f_peaks;
}
//------------------------------------------------------------------------------------//
//main.cpp
int data[64]={
14, 30, 35, 34, 34, 40, 46, 45, 30, 4, -26, -48, -55, -49, -37,
-28, -24, -22, -13, 6, 32, 55, 65, 57, 38, 17, 1, -6, -11, -19, -34,
-51, -61, -56, -35, -7, 18, 32, 35, 34, 35, 41, 46, 43, 26, -2, -31, -50,
-55, -47, -35, -27, -24, -21, -10, 11, 37, 58, 64, 55, 34, 13, -1, -7
};
int main(){
const unsigned int SAMPLE_RATE = 48*1000; //48khz
auto result = FFT(data,64,SAMPLE_RATE);
std::cout << result[0] << " " << result[1] << " " << result[2] << " " << result[3] << std::endl;
delete[] result;
return 0;
}