Develop Reference

How do I fix the resource leak in my RSA algorithm (java)?

I am attempting to make an RSA algorithm and i'm not sure how to close my scanner. I have attempted to use .close(); for instance trying to place it at the end of my RSA class but to no avail. Most likley I am just not putting it in the correct place or because i keep getting the following error in Visual Studio on my line 19:
Help much appreciated.
import java.util.*;
public class RSA {
static int gcd(int m, int n) {
while (n != 0) {
int r = m % n;
m = n;
n = r;
}
return m;
}
public static void main(String args[]) {
int p = 0, q = 0, n = 0, e = 0, d = 0, phi = 0;
int nummes[] = new int[100];
int encrypted[] = new int[100];
int decrypted[] = new int[100];
int i = 0, j = 0, nofelem = 0;
Scanner sc = new Scanner(System.in);
String message;
System.out.println("Enter the Message to be encrypted:");
message = sc.nextLine();
System.out.println("Enter value of p and q\n");
p = sc.nextInt();
q = sc.nextInt();
n = p * q;
phi = (p - 1) * (q - 1);
for (i = 2; i < phi; i++)
if (gcd(i, phi) == 1) break;
e = i;
for (i = 2; i < phi; i++)
if ((e * i - 1) % phi == 0) break;
d = i;
for (i = 0; i < message.length(); i++) {
char c = message.charAt(i);
nummes[i] = c - 96;
}
nofelem = message.length();
for (i = 0; i < nofelem; i++) {
encrypted[i] = 1;
for (j = 0; j < e; j++)
encrypted[i] = (encrypted[i] * nummes[i]) % n;
}
System.out.println("\n Encrypted message\n");
for (i = 0; i < nofelem; i++) {
System.out.print(encrypted[i]);
System.out.print((char) (encrypted[i] + 96));
}
for (i = 0; i < nofelem; i++) {
decrypted[i] = 1;
for (j = 0; j < d; j++)
decrypted[i] = (decrypted[i] * encrypted[i]) % n;
}
System.out.println("\n Decrypted message\n ");
for (i = 0; i < nofelem; i++)
System.out.print((char) (decrypted[i] + 96));
return;
}
}

static string weird behavior Diamond Star Pattern problem

I'm trying to solve this problem given a number 5, we display:
*
*****
*********
*****
*
And so on. So you give it a number and it format it for you like above. I tried to solve it using this code bellow and I can't see where the problem is in my code.
public class Exe01 {
public static String space = "";//global space var
public static String ast = "";//global * var
public static String adjustAst(int numOfAst) {
Exe01.ast = "";
for (int i = numOfAst; i > 0; i--) {
Exe01.ast+="*";
}
return Exe01.ast;
}
public static String adjustSpaces(int numOfSpaces) {
Exe01.space = "";
for (int i = numOfSpaces; i > 0; i--) {
Exe01.space = Exe01.space + " ";
}
return Exe01.space;
}
public static void showAst(int num) {
if (num <= 0 || num % 2 == 0)
System.out.println("arg to the function need to be positive and odd");
else if (num == 1)
System.out.println("*");
else {
int mid = (int) (num / 2);
int numberOfSpaces = num - 1;
for (int i = 0; i < num; i++) {
int k = 0;
if (i < mid) {
k = k * 2 + 1;
System.out.println(Exe01.adjustSpaces(numberOfSpaces) + Exe01.adjustAst(k));
numberOfSpaces = numberOfSpaces - 2;
} else if (i == mid) {
numberOfSpaces = 0;
k = k * 2 + 1;
System.out.println(Exe01.adjustSpaces(numberOfSpaces) + Exe01.adjustAst(k));
numberOfSpaces = numberOfSpaces + 2;
} else {
k = k - 4;
System.out.println(Exe01.adjustSpaces(numberOfSpaces) + Exe01.adjustAst(k));
numberOfSpaces = numberOfSpaces + 2;
}
}
}
}
public static void main(String args[]) {
Exe01.showAst(5);
}
}
At compilation time it gives me this:
*
*
*

I am trying to cancel factorials in Java

I'm trying to calculate the number of rCombinations for a project for school and I can't seem to get my method to return the correct values.
I talked to my professor and he recommended canceling the common factors in factorials. Such that
35!/32! = 35*34*33.
This is what I have so far.
public static long rCombinations(int n, int r) {
int q = n-r;
long x = 1;
for(int i = r; i <= r; i ++)
{
x = n*(n-i);
}
return x/factorial(r);
}

You can use this implementation for calculating large factorial of numbers without BigInteger as follows :
import java.util.Scanner;
public class N_Faktorial {
public static void main(String[] args) {
int u = 1, A[] = new int[9999999];
Scanner scan = new Scanner(System.in);
System.out.print("n=");
int n = scan.nextInt();
A[1] = 1;
for (int i = 1; i <= n; i++) {
for (int j = 1; j <= n; j++) {
A[j] *= i;
}
for (int j = 1; j <= n; j++) {
if (A[j] > 9) {
A[j + 1] += A[j] / 10;
A[j] %= 10;
}
if (A[u + 1] != 0) {
u++;
}
}
}
for (int i = u; i >= 1; i--) {
System.out.print(A[i]);
}
//when n>=24 count of digit of n! is equal to n+1.
System.out.println("\n Result : " + n + " count of digit " + u);
}
}
After this you need some solution for doing division operation.
Hope it helps!.

For n!/m!, where n >= m
int out = 1;
for(int i = n; i <= m; i++)
out *= i;
For n!/m!, where n <= m
double out = 1;
for(int i = n; i <= m; i++)
out /= i;
In both cases, out = n!/m!
Note that it's still easy to overflow an int, 55!/49! is too big

Getting NZEC in Java for PARTSUM on SPOJ

Array T[] has been used to store the sum of all possible contiguous combinations. And at each step, I am checking whether it is atleast k or not and that value is stored in the variable val. Below is the Java Code:
import java.util.Arrays;
import java.util.Scanner;
class Codechef {
public static void main(String[] args) throws java.lang.Exception {
Scanner sc = new Scanner(System.in);
long t = sc.nextLong();
while (t > 0) {
int n = sc.nextInt();
long k = sc.nextLong();
long p = sc.nextLong();
long a[] = new long[n];
long T[] = new long[((n * (n + 1)) / 2)];
Arrays.fill(T, -1);
long sum = 0, x = 0, val = p, f = 0;
int i = 0;
for (i = 0; i < n; i++) {
a[i] = sc.nextLong();
sum = sum + a[i];
x = sum % p;
T[i] = x;
if (T[i] == k)
f = 1;
else if (T[i] > k && T[i] < val)
val = T[i];
}
if (f != 1) {
for (int j = i - 1; j > 0; j--) {
for (int m = 0; m < j; m++) {
x = T[j] - T[m];
if (x < 0)
x += p;
T[i] = x;
if (T[i] == k) {
f = 1;
break;
}
else if (T[i] > k && T[i] < val)
val = T[i];
i++;
}
if (f == 1)
break;
}
}
if (f == 1)
System.out.println(k);
else
System.out.println(val);
t--;
}
}
}
The above is the code for PARTSUM- Partial Sums on SPOJ. What could be the possible error?
Previously I was getting Runtime error NZEC on submit. Now that has been corrected and now I am getting TLE. Any optimization?

multidimensional array sorting by column in java

i need some help in this problem, there are three columns namely phase#, block# and lot#, i needed to sort the phase# in ascending order while the other two will be sorted accordingly to its phase#:
Problem:
Phase# 1-2-1-3-1-2-1
Block# 1-1-2-1-2-1-1
Lot# 1-2-2-2-3-1-1
What it should be like:
Phase# 1-1-1-1-2-2-3
Block# 1-2-2-1-1-1-1
Lot# 1-2-3-1-2-1-2
here's what I've got so far:
import java.io.*;
import java.util.*;
public class test{
public static void main(String[] args) throws IOException{
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
int x = 7;
int y = 3;
int[][] phase= new int[x][y];
int swap = 0, temp, i, min = 0;
phase[0][0] = 1;
phase[1][0] = 2;
phase[2][0] = 1;
phase[3][0] = 3;
phase[4][0] = 1;
phase[5][0] = 2;
phase[6][0] = 1;
phase[0][1] = 1;
phase[1][1] = 1;
phase[2][1] = 2;
phase[3][1] = 1;
phase[4][1] = 2;
phase[5][1] = 1;
phase[6][1] = 1;
phase[0][2] = 2;
phase[1][2] = 2;
phase[2][2] = 2;
phase[3][2] = 2;
phase[4][2] = 3;
phase[5][2] = 1;
phase[6][2] = 1;
System.out.println("UNSORTED: \n");
System.out.println("Phase#\tBlock#\tLot#");
for(i = 0; i < phase.length; i++){
System.out.print(phase[i][0] + "\t" + phase[i][1] + "\t"+phase[i][2]);
System.out.print("\n");
}
System.out.println("\nSORTED:\n");
for(i = 0; i <= phase.length- 1; i++){
min = i;
for(int a = i+1; a < phase.length; a++ ){
if(phase[a][0]<phase[a][0]){
temp=phase[i][0];
phase[i][0]=phase[a][0];
phase[a][0]=temp;
}
}
}
System.out.println("Phase#\tBlock#\tLot#");
for(int j = 0; j < phase.length; j++){
System.out.print(phase[j][0] + "\t" + phase[j][1] + "\t"+phase[j][2]);
System.out.print("\n");
}
}
}

Implement Comparator interface as (int [] left, int[] right) -> left[0]-right[0] and pass it to Arrays.sort() method:
Arrays.sort(phase, (int [] left, int[] right) -> left[0]-right[0]);