How to determine your machine is “Little Endian” or “Big Endian”.

What is big and Little Endian ?

Little and big endian are two ways of storing multibyte data-types ( int, float, etc). In little endian machines, last byte of binary representation of the multibyte data-type is stored first. On the other hand, in big endian machines, first byte of binary representation of the multibyte data-type is stored first.

Big Endian(Wikipedia)

Little Endian(Wikipedia)

Is there a quick way to determine endianness of your machine?
There are n no. of ways for determining endianness of your machine. Here is one quick way of doing the same.

#include <stdio.h>
int main()
{
   unsigned int i = 1;
   char *c = (char*)&i;
   if (*c)   
       printf("Little endian");
   else
       printf("Big endian");
   getchar();
   return 0;
}

In the above program, a character pointer c is pointing to an integer i. Since size of character is 1 byte when the character pointer is de-referenced it will contain only first byte of integer. If machine is little endian then *c will be 1 (because last byte is stored first) and if machine is big endian then *c will be 0.

Counting Digits from given Range

Imagine you sell those metallic digits used to number houses, locker doors, hotel rooms, etc. You need to find how many of each digit to ship when your customer needs to number doors/houses:
1 to 100
51 to 300
1 to 2,000 with zeros to the left
The obvious solution is to do a loop from the first to the last number, convert the counter to a string with or without zeros to the left, extract each digit and use it as an index to increment an array of 10 integers.
I wonder if there is a better way to solve this, without having to loop through the entire integers range.
GitHub Link
Thanx to mathematician’s Post that helped me to understand the complexity of problem, i just understood the equation and converted it to code. Enjoy !

Minimum cost flow House coloring with three colors

There are a row of houses, each house can be painted with three colors red, blue and green. The cost of painting each house with a certain color is different. You have to paint all the houses such that no two adjacent houses have the same color. You have to paint the houses with minimum cost. How would you do it?

Note: Painting house-1 with red costs different from painting house-2 with red. The costs are different for each house and each color.

Approach:
Dynamic Programming solution:
we can paint the i’th house with blue, red or green.

Enter No. of Houses to paint : 6
1 4 5
1 3 9
6 7 2
9 6 4
3 5 2
6 7 4

Minimum Cost to paint all houses are 20
#include <stdio.h>
#include <stdarg.h>
#define COLOR 3
#define MAX(a,b) ((a) > (b) ? a : b)
#define MIN(a,b) ((a) < (b) ? a : b)
#define R 0
#define B 1
#define G 2
#define Color 3


int min( int num, ... )
{
    va_list arguments;
    int min=0;
    int tmp=0;
    /* Initializing arguments to store all values after num */
    va_start ( arguments, num );
    /* Sum all the inputs; we still rely on the function caller to tell us how
     * many there are */
    min = va_arg ( arguments, int );
    //printf("\n1st|%d|\n",min);
    for ( int x = 1; x < num; x++ )
    {
		tmp = va_arg(arguments,int);
		min = MIN(min,tmp);
    }
    va_end ( arguments );
    // Cleans up the list
	//printf("\nMin is %d", min);
    return min;
}
typedef struct {
    int  color;
    int cost;
    //struct nodee *root;
}node;
int main()
{
	node cost[3];
	int house = 3;
	printf("Enter No. of Houses to paint : ");
	scanf("%d",&house);
	int color[house][COLOR];
//	int ji=0;
	for(int i=0; i<house;++i){
		for(int j=0; j<COLOR;++j){
				scanf("%d",&color[i][j]);
//				color[i][j]= ++ji;
			}

		}
	//cost[0].cost=color[0][R];cost[1].cost=color[0][B];cost[2].cost=color[0][G];
	for(int i= 0; i< Color ;i++){
			cost[i].cost=color[0][i];
			cost[i].color = i;
		} // Initial Submission of values, and colour
//	printf("\nA.cost\t%d(%d)\tB.cost\t%d(%d)\tC.cost\t%d(%d)\n",cost[0].cost,cost[0].color,cost[1].cost,cost[1].color,cost[2].cost,cost[2].color);
	//A.color = R; B.color = B; C.color = G;
	int tmp_B=0,tmp_G=0,tmp_R=0;
	//printf("\nR_cost\t%d\tB_cost\t%d\tG_cost\t%d\n",R_cost,B_cost,G_cost);
	for(int i=1; i<house;++i)
		{
			for(int j= 0; j< Color ;j++){
				if(cost[j].color == R){
						if(color[i][B] < color[i][G]){
							cost[j].cost = cost[j].cost + color[i][B];
							cost[j].color = B;
							//add_linked_list();
							//cost[j].root = malloc(sizeof(struct node));
							//cost[j].root->next = 0;
							//cost[j].root->x = color[i][B];
						}else{
								cost[j].cost = cost[j].cost + color[i][G];
								cost[j].color = G;
						}
					}else if(cost[j].color == B){
							if(color[i][R] < color[i][G]){
								cost[j].cost = cost[j].cost + color[i][R];
								cost[j].color = R;
							}else{
									cost[j].cost = cost[j].cost + color[i][G];
									cost[j].color = G;
								}
						}else{
								//Case for G
								if(color[i][R] < color[i][B]){
									cost[j].cost = cost[j].cost + color[i][R];
									cost[j].color = R;
									}else{
											cost[j].cost = cost[j].cost + color[i][B];
											cost[j].color = B;
										}
							}
//			printf("\nA.cost\t%d(%d)\tB.cost\t%d(%d)\tC.cost\t%d(%d)\n",cost[0].cost,cost[0].color,cost[1].cost,cost[1].color,cost[2].cost,cost[2].color);
			}
			/*
			if(A.color == )
			//R_cost = min(2,color[i][B],color[i][G])+R_cost;
			if(color[i][B] < color[i][G]){

				tmp_B = R_cost + color[i][B];
				}else{
						tmp_G = R_cost + color[i][G];
					}

			//B_cost = min(2,color[i][R],color[i][G])+B_cost;
			if(color[i][R] < color[i][G]){

				tmp_R = B_cost + color[i][R];
				}else{
						tmp_G = B_cost + color[i][G];
					}
			//G_cost = min(2,color[i][B],color[i][R])+G_cost;
			if(color[i][R] < color[i][B]){

				tmp_R = G_cost + color[i][R];
				}else{
						tmp_B = G_cost + color[i][B];
					}
			R_cost = tmp_R;
			B_cost = tmp_B;
			G_cost = tmp_G;
			//printf("\n G %d:%d",color[i][B],color[i][R]);
			*/
//			printf("\nA.cost\t%d(%d)\tB.cost\t%d(%d)\tC.cost\t%d(%d)\n",cost[0].cost,cost[0].color,cost[1].cost,cost[1].color,cost[2].cost,cost[2].color);
		}
	printf("\nMinimum Cost to paint all houses are %d\n",min(3,cost[0].cost,cost[1].cost,cost[2].cost));
}

How Many Ip Address !!!

Given a string containing only digits, restore it by returning all possible valid IP address combinations.
For example:
Given “25525511135”,
return [“255.255.11.135″, “255.255.111.35”]{hint:recursion,backtrack}

Here is the Solution ……
it was taken me about 5 hours to solve see !!!

//cc Arun Kumar Gupta

import java.util.*;
public class AllIpAddress
{
public static void main (String [] args)
{
Scanner sc = new Scanner(System.in);
String input = sc.next();
int[] intArray = new int[input.length()];
int length = input.length();

for (int i = 0; i < input.length(); i++) {
intArray[i] = Character.digit(input.charAt(i), 10);
//System.out.println(intArray[i]);
}
int i = 0 , j = 1 , k = 2;
AllIpAddress ip = new AllIpAddress();
ip.Ipaddress(intArray , i , j , k , length-1);

}
void Ipaddress(int [] intArray , int i , int j , int k , int length)
{
try{
int where = 0 ,change = 0;
int p1 =createIP( intArray , -1 , i);
int p2 =createIP( intArray , i ,  j );
int p3 =createIP( intArray ,  j , k );
int p4 =createIP( intArray ,  k ,  length );
//System.out.println(“**********Garbage”+p1+”.”+p2+”.”+p3+”.”+p4);
//System.out.println(“i = “+i+”j = “+j+”k = “+k);
if((p1<=255)&&(p2<=255)&&(p3<=255)&&(p4<=255)&&(p4>0))
{
System.out.println(p1+”.”+p2+”.”+p3+”.”+p4);
}
if(p4 >255)
{
//if(k != j)
//++k;
where =4;
//System.out.println(“Problem at P4″);
}
else if(p3>255)
{
//if(j != i)
//++j;
//–k;
where = 3;
//System.out.println(“Problem at P3″);
}
else if(p2>255)
{
//++i;
where = 2;
//System.out.println(“Problem at P2″);
}
else if(p1>255)
{

//System.out.println(“Problem at P1″);
System.exit(0);
}

if((k == length) && (j+1 == k))
{
//System.out.println(“if((k == length) && (j+1 == k))”);
//System.out.println(i+”_”+j+”_”+k);
++i;
j = i+1;
k = j+1;
change = 1;
//System.out.println(i+”_”+j+”_”+k);

}
if((k == length) &&(change == 0) )
{
//System.out.println(“if((k == length) &&(change == 0) )”);
++j;
k = j+1;
change = 0;
}
else if(change == 0)
{
if( (k) < length )
++k;
}
/*if(where ==4)
{
++k;
}
if(where ==3)
{
++j;
–k;
}
if(where ==2)
{
++i;
–j;
}
/*if(k==length)
{
–k;
–j;
}*/
Ipaddress(intArray , i , j , k , length);
}
catch(ArrayIndexOutOfBoundsException e){
//System.out.println(“Exception thrown  :” + e);
}
}
static int createIP(int [] intArray , int start , int end)
{
//System.out.println(“I am at createIP()start = “+start+”\tend = “+end);
int val = 1 , fina = 0;
for(int e =end ; e>start ; –e)
{
fina = intArray[e]*val + fina;
val = val*10;
}
return fina;
}
}

Prime Generator

Sorry for late post i was too busy ….
this is a new problem 
Peter wants to generate some prime numbers for his cryptosystem. Help him! Your task is to generate all prime numbers between two given numbers!

Input

The input begins with the number t of test cases in a single line (t<=10). In each of the next t lines there are two numbers m and n (1 <= m <= n <= 1000000000, n-m<=100000) separated by a space.

Output

For every test case print all prime numbers p such that m <= p <= n, one number per line, test cases separated by an empty line.

Example

Input:
2
1 10
3 5

Output:
2
3
5
7

3
5




Solution :


CC Arun Kumar Gupta

import java.util.*;
public class FastestPrime
{
public static void main (String [] args)
{
Scanner sc = new Scanner(System.in);
int test_cases = sc.nextInt();
if((test_cases <=10) && (test_cases > 0))
{
for(int i = 0 ; i {
int m = sc.nextInt();
int n = sc.nextInt();
if((m<= 1000000000) &&(n<=1000000000)&&(n>0)&&(m>0))
{
if((n-m) <= 100000)
{
if((m % 2) == 0)
++m;
for(int j = m ; j<= n ; ++j)
{
NextNum(j);
j = j+ 1;

}
}
}
System.out.println();
}
}


}
static void NextNum(int m)
{
int div = 3;
int array [] = new int[1000];
int rem = 1 ;
while((rem != 0) && (div <= (m/2)))
{
rem = m%div;
div = div+2;
}
if(rem != 0)
{
System.out.println(m);
}

}
}



Max gain from given stock values



Given ticker value for a stock, for next n days, given what is the max profit that you can make ?
Eg – the max profit you can make is buy at time t1 @ 5 and sell @ t2 when stock was 12, to get max Profit of 7 dollars.

time – Stock Price

t0 – 10
t1 – 5
t2 – 12
t3 – 7
t4 – 12

Also – you can only trade once i.e you can buy and sell only 1 time.

so here is the solution of that problem .that problem is nothing just think like that if we have only one day stock values so we can buy or sell on that day only , so for general we can find the for up to kth day and we can find out for the k+1’th day ..

so algo is that maintain the 3 things first two pointer of buy and sell and one pointer of minimum values .we can make it in O(n) only



Just make a new array which contains the “lookahead” view, where we can see, which potential highest value we can gaini in future.

Another array just contains the lowest value so far. When the difference between the two arrays is max, there is the buying point. Selling point is, when the falling edge of the max array is reached.


public void highestGain(int[] prices) {
        int[] maxPrices = new int[prices.length];
        int[] minPrices = new int[prices.length];
        maxPrices[maxPrices.length-1] = prices[prices.length-1];
        minPrices[0] = prices[0];
        for(int i = 1; i <prices.length; i++) {
            int right = prices.length-i-1;
            minPrices[i] = Math.min(minPrices[i-1], prices[i]);
            maxPrices[right] = Math.max(maxPrices[right+1], prices[right]);
        }
        System.out.println("MaxPrices: " + Arrays.toString(maxPrices));
        System.out.println("MinPrices: " + Arrays.toString(minPrices));

// find when to buy (when the difference of min/max is highest)

        int maxDifference = maxPrices[0] - minPrices[0];
        int maxDifferencePos = 0;
        for(int i=0; i<minPrices.length; i++) {
            int difference = maxPrices[i] - minPrices[i];
            if(maxDifference < difference) {
                maxDifference = difference;
                maxDifferencePos = i;
            }
        }
        // Now find the falling edge of max prices - there was the last peak
        int sellPos = maxDifferencePos+1;
        int lastPrice = maxPrices[maxDifferencePos];
        for(; sellPos < maxPrices.length; sellPos++) {
            if(lastPrice > maxPrices[sellPos]) {
                sellPos --;
                break;
            }
        }

System.out.println("Ideal to buy/sell: " + maxDifferencePos + ":" + sellPos);

    }



Alien Chef


A new programming Problem…..

//http://www.codechef.com/problems/DOWNLOAD
/*


The aliens living in outer space are very advanced in technology, intelligence and everything, except one, and that is Cooking. Each year they spend millions of dollars in research, to crack famous recipes prepared by humans.

Recently they came to know about Khana-Academy, a non-profit organization streaming free cooking lesson videos on earth. There are N recipes, numbered 1 to N, and the video of the ith recipe is live in the time interval [Si, Ei]. An alien can visit earth but can not survive for more than just a small moment (earth is so advanced in pollution). An alien visits the earth at an integer time t and instantly downloads the complete video of all the lessons that are live at that moment of time t and leaves earth immediately. You are given the visiting times of a small group of K aliens. Find the number of different recipes aliens can learn by watching the downloaded videos. Not just one group of aliens, there are Q such groups, so you have to find the answer for each of these Q groups.
Input

The first line has an integer N. Each of the following N lines has two integers Si Ei. The next line has an integer Q, the number of groups. Each of the following Q lines has information of a group of aliens. The first integer is K, the number of aliens in that group, followed by K integers in the same line, the integer visiting times t of the aliens.


1 ≤ N ≤ 100000 (105)

1 ≤ Q ≤ 5000 (5 103)
1 ≤ K ≤ 20
1 ≤ Si, Ei, t ≤ 1000000000 (109)
Si < Ei

Output


For each of the Q groups, output the number of different recipes that group of aliens can learn by watching the downloaded videos.

Example

Input:

4
1 4
3 10
2 6
5 8
3
1 5
2 2 6
3 1 10 9

Output:

3
4
2

Explanation:

Given videos of 4 recipes in the following closed intervals.
1. [ 1 , 4 ]
2. [ 3 , 10 ]
3. [ 2 , 6 ]
4. [ 5 , 8 ]

In the first query, only one alien arrives at t = 5 and can download 3 recipes 2, 3, 4.


In the second query, two aliens arrive at t = 2 and 6. They can learn all the 4 recipes.


In the third query, three aliens arrive at t = 1, 10 and 9. They can learn only two recipes, 1 and 2.


*/




import java.util.*;
import java.lang.*;
/*public class Array
{
int num[]  = new int[20];



}

*/
public class AlienChefs
{
static int aaa[] = new int[100000];
static int end ;
//leng = 1;
static int start ;
public static void main(String [] args)
{

Scanner sc = new Scanner(System.in);
int n = sc.nextInt();
if((0
{
int a[] = new int[2*n];
int add = 10;
for(int i = 0 ; i<(2*n) ; ++i)
{
//System.out.println(“Inside”);

a[i] = sc.nextInt();
if( (0
{
if((i%2) == 1   )
{
//System.out.println(“Inside”);
if((a[i-1] > a[i]))
System.exit(0);
}

}
else 
System.exit(0);
}
int groups = sc.nextInt();
//System.out.println(“********************”);
//int address[] = new int[groups];
for(int i = 0 ; i< groups; ++i)
{
int count = 0 ;
int alen = 0 ;
int times = sc.nextInt();
for(int j =0 ;j
{

alen = sc.nextInt();
if((0
{
//System.out.println(alen);
count = count+ cc(a , alen);

}


}
start = end – start;
start = start +end + add ;
end = start;
aaa[start] = 1000;
System.out.println(count);

}
}

}
static int cc(int a [] , int val)
{
int count = 0 ;

for(int i = 0 ; i< a.length; i++)
{ //static int a;
int abc =0;


if((a[i] <= val)&& (val <= a[i+1] ))
{
//System.out.println(“***************************************”);
abc = check(aaa , i);
if( abc == 0)
{
++count;
}

}
++i;

}
//System.out.println(“Count Returned :”+count);

return count;
}
static int check(int qw [], int i)
{
//System.out.println(“Check Function is called “);
//System.out.println(start+”:”+end);
//System.out.println(“i = “+i);
for(int j = start ; j<=end ; j++)
{
if(qw[j] == i)
return 1;
}
qw[end] = i;
//System.out.println(qw[end]+”   :::::::Value Added”);
++end;
return 0;

}
}