2016 Update

Task/Matrix-arithmetic/Java/matrix-arithmetic-1.java

@@ -0,0 +1,55 @@
+import java.util.Scanner;
+
+public class MatrixArithmetic {
+	public static double[][] minor(double[][] a, int x, int y){
+		int length = a.length-1;
+		double[][] result = new double[length][length];
+		for(int i=0;i<length;i++) for(int j=0;j<length;j++){
+			if(i<x && j<y){
+				result[i][j] = a[i][j];
+			}else if(i>=x && j<y){
+				result[i][j] = a[i+1][j];
+			}else if(i<x && j>=y){
+				result[i][j] = a[i][j+1];
+			}else{ //i>x && j>y
+				result[i][j] = a[i+1][j+1];
+			}
+		}
+		return result;
+	}
+	public static double det(double[][] a){
+		if(a.length == 1){
+			return a[0][0];
+		}else{
+			int sign = 1;
+			double sum = 0;
+			for(int i=0;i<a.length;i++){
+				sum += sign * a[0][i] * det(minor(a,0,i));
+				sign *= -1;
+			}
+			return sum;
+		}
+	}
+	public static double perm(double[][] a){
+		if(a.length == 1){
+			return a[0][0];
+		}else{
+			double sum = 0;
+			for(int i=0;i<a.length;i++){
+				sum += a[0][i] * perm(minor(a,0,i));
+			}
+			return sum;
+		}
+	}
+	public static void main(String args[]){
+		Scanner sc = new Scanner(System.in);
+		int size = sc.nextInt();
+		double[][] a = new double[size][size];
+		for(int i=0;i<size;i++) for(int j=0;j<size;j++){
+			a[i][j] = sc.nextDouble();
+		}
+		sc.close();
+		System.out.println("Determinant: "+det(a));
+		System.out.println("Permanent: "+perm(a));
+	}
+}