Java function snippets, Matrix, LCM, GCD

JavaSnippets.java

	
	// used to print format print. %n is new line. dont use \n
	// http://docs.oracle.com/javase/tutorial/java/data/numberformat.html
	System.out.format("The value of sum is: %.2f%n", 4650/100);
	
	//Rotates a matrix right
	public static void rotateRight(char[][] matrix) { 
		int cols = matrix[0].length;
		int rows = matrix.length;
		
		char[][] tmp = new char[matrix.length][matrix.length];
		
		// rotate 
		for(int i=0; i<rows; i++){
			for(int j=0; j<cols; j++) {
				tmp[j][rows-1-i] = matrix[i][j];
			}
		}
		
		// copy back 
		for(int i=0; i<rows; i++){
			for(int j=0; j<cols; j++) {
				matrix[i][j] = tmp[i][j];
			}
		}
	}



	//prints n by n matrix    
	public static void printMatrix(int[][] matrix) {
		int cols = matrix[0].length;
		int rows = matrix.length;
		
		for(int i=0; i<rows; i++){
			for(int j=0; j<cols; j++) {
				 System.out.print(matrix[i][j] + " ");
			}
			System.out.println("");
		}
	}

    // GCD for arrays
    public static int gcd(int[] input) {
    	int result = input[0];
        for(int i = 1; i < input.length; i++) result = gcd(result, input[i]);
        return result;
    }
    
    //FAST GCD due to bitwise manipulations
    public static int gcd(int a, int b)
    {
        while(b>0) b ^= a ^= b ^= a %= b;
        return a;
    }
    // Normal euclidean GCD 
    public static int GCD(int a, int b) {
    	   if (b==0) return a;
    	   return GCD(b,a%b);
    }
    
    //GCD LONG 
    public static long gcd(long[] input) {
        long result = input[0];
        for(int i = 1; i < input.length; i++) result = GCD(result, input[i]);
        return result;
    }
    
    public static long GCD(long a, long b) {
    	   if (b==0) return a;
    	   return GCD(b,a%b);
    }