check if array is sorted using recursion.

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Sun Jun 30 2024 08:15:40 GMT+0000 (Coordinated Universal Time)

Saved by @vishnu_jha #c++ #dsa #recursion #array

bool isArraySorted (int arr[],int size) {
  if (size == 0 || size == 1) 
    return true;
  if (arr[0]>arr[1]) 
    return false;
  else {
    bool remainingPart = isArraySorted(arr+1,size-1); 
    return remainingPart;
  }
  
}

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#c++ #algorithms #interviewquestions #arrays

Kadane’s Algorithm

int maxSubArraySum(int a[], int size) 
{ 
int max_so_far = 0, max_ending_here = 0; 
for (int i = 0; i < size; i++) 
{ 
	max_ending_here = max_ending_here + a[i]; 
	if (max_ending_here < 0) 
		max_ending_here = 0; 

	/* Do not compare for all elements. Compare only 
		when max_ending_here > 0 */
	else if (max_so_far < max_ending_here) 
		max_so_far = max_ending_here; 
} 
return max_so_far; 
}

#java #gfg #geeksforgeeks #lecture #recursion #rope cutting

Rope Cutting Problem

import java.io.*;
import java.util.*;

class GFG 
{
	static int maxCuts(int n, int a, int b, int c)
	{
		if(n == 0) return 0;
		if(n < 0)  return -1;

		int res = Math.max(maxCuts(n-a, a, b, c), 
		          Math.max(maxCuts(n-b, a, b, c), 
		          maxCuts(n-c, a, b, c)));

		if(res == -1)
			return -1;

		return res + 1; 
	}
  
    public static void main(String [] args) 
    {
    	int n = 5, a = 2, b = 1, c = 5;
    	
    	System.out.println(maxCuts(n, a, b, c));
    }
}

**8.11 (Game: nine heads and tails)

#include <iostream>
#include<cmath>
#include<ctime>
#include<string>
#include <iomanip>
#include <fstream>

using namespace std;




void decToBinary(int n)
{
    // array to store binary number 
    int binaryNum[3][3];
    
    //converting to binary 
    for (int i = 0; i < 3; i++) 
    {
        for (int j = 0; j < 3; j++)
        {
            binaryNum[i][j] = n % 2;
            n = n / 2;

        }
     }       

    // printing binary> array in reverse order 
    for (int i = 3-1; i >= 0; i--){
        for (int j = 3 - 1; j >= 0; j--)
        {
            if (binaryNum[i][j] == 0)
                cout << "H" << " ";
            else
                cout << "T" << " ";
        }
        cout << endl;
    }
    
 }

int main()
{
    int n;
    cout << "Enter a decimal number between 1 and 512 ";
    cin >> n;

    decToBinary(n);
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}

Write a program that displays the first 100 emirps

#include <iostream>
#include<cmath>
#include<ctime>
#include<string>
#include <iomanip>
#include <fstream>

using namespace std;


bool primeNumber(int n);
bool Emirp(int n);
int reversal(int n);
int recursive(int a, int b);

int main()
{
	
	int count = 0;
	int number = 13;
	while (count <= 100)
	{
		if (Emirp(number))
		{
			count++;
			if (count % 10 == 0)
				cout << setw(7) << number << endl;
			else
				cout << setw(7) << number;
		}
		number++;
	}
		

}
bool primeNumber(int n) {
	
		for (int i = 2; i <= n / 2; i++) {
			
			if (n % i == 0) {

				return false;
			}
		}
		return true;
}

bool Emirp(int n) {
	

	return primeNumber(n) && primeNumber(reversal(n));
	
}

int reversal(int n) {
	
		if (n < 10) {
			
				return n;
			
		}
		return recursive(n % 10, n / 10);
	
}

int recursive(int a, int b) {

	if (b < 1) {

		return a;

	}
	return recursive(a * 10 + b % 10, b / 10);
	
}

Difference Between ios::ate and ios::app

https://stackoverflow.com/questions/10359702/c-filehandling-difference-between-iosapp-and-iosate#:~:text=ios%3A%3Aapp%20%22set%20the,file%20when%20you%20open%20it.&text=The%20ios%3A%3Aate%20option,to%20the%20end%20of%20file.

#include<iostream>
using namespace std;
bool issafe(int** arr,int x,int y,int n){
    for(int row=0;row<=x;row++){
        if(arr[x][y]==1){
            return false;
        }
    }
    int row=x;
    int col=y;
    while(row>=0 && col>=0){
        if(arr[row][col]==1){
            return false;
        }
        row--;
        col--;
    }
     row=x;
     col=y;
    while(row>=0 && col<n){
        if(arr[row][col]==1){
            return false;
        }
        row--;
        col++;
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}
bool nqueen(int** arr,int x,int n){
    if(x>=n){
        return true;
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    for(int col=0;col<=n;col++){
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        }
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}
int main(){
    int n;
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        }
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    return 0;
}

#java #gfg #geeksforgeeks #2d #array #matrix #addition #practice

Adding two matrices

class Solution
{
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}

#java #gfg #geeksforgeeks #2d #array #matrix #practice #sum

Sum of upper and lower triangles

class Solution
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#java #gfg #geeksforgeeks #2d #array #matrix #practice #multiplication

Multiply the matrices

class Solution
{
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}

#java #gfg #geeksforgeeks #2d #array #matrix #practice #determinant

Determinant of a Matrix

class Solution
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#java #gfg #geeksforgeeks #2d #array #matrix #practice #exchangecolumns

Exchange matrix columns

class Solution
{
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}

#java #gfg #geeksforgeeks #2d #array #matrix #practice #reversingcolumns

Reversing the columns of a Matrix

class Solution
{
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       for(int i=0; i<matrix.length; i++){
           for(int j=0; j<matrix[i].length/2; j++)
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               int temp = matrix[i][j];
               matrix[i][j] = matrix[i][matrix[i].length-j-1];
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}

#java #gfg #geeksforgeeks #2d #array #matrix #practice #interchangingrows

Interchanging the rows of a Matrix

class Solution
{
    //Function to interchange the rows of a matrix.
    static void interchangeRows(int matrix[][])
    {
       for(int i=0;i<matrix.length/2;i++){
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               int temp=matrix[i][j];
               matrix[i][j]=matrix[matrix.length-i-1][j];
               matrix[matrix.length-i-1][j]=temp;
           }
       } 
    }
}

#java #gfg #geeksforgeeks #2d #array #matrix #practice #booleanmatrix

class Solution
{
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    void booleanMatrix(int matrix[][])
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        //using two list to keep track of the rows and columns 
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        int row[] = new int[r];
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        for(int i =0; i < r; i++)
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            {
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                if(row[i] == 1 || col[j] == 1){
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            }
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#java #gfg #geeksforgeeks #2d #array #matrix #practice #beautifulmatrix

Make Matrix Beautiful

class Solution 
{
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    static int findMinOperation(int matrix[][], int n)
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        int sumRow[] = new int[n];
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        //calculating sumRow[] and sumCol[] array.
        for(int i = 0; i < n; i++)
        {
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            {
                sumRow[i] += matrix[i][j];
                sumCol[j] += matrix[i][j];
                  
            }
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        int maxSum = 0;
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            int diff = Math.min(maxSum - sumRow[i], maxSum - sumCol[j]);
            
            //adding difference in corresponding cell, 
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            matrix[i][j] += diff;
            sumRow[i] += diff;
            sumCol[j] += diff;
            
            //updating the result.
            count += diff;
            
            //if ith row is satisfied, incrementing i for next iteration.
            if (sumRow[i] == maxSum)
                ++i;
            
            //if jth column is satisfied, incrementing j for next iteration.
            if (sumCol[j] == maxSum)
                ++j;
        }
        //returning the result.
        return count;
    }
}

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