microsoft_Margaret

package microsoft_competition;

import java.util.ArrayList;
import java.util.Scanner;

public class MatrixMultiplication {
    private int a[][];
    private int b[][];
    private int sum[][];

    public void calculateSum(int a[][], int b[][]) {
        sum = new int[a.length][b[0].length];

        // Iterate through rows of a
        for (int i = 0; i < a.length; i++) {

            // In the current row of A, loop through each column value
            for (int j=0; j<b[0].length; j++){

                for(int k=0; k< a[0].length; k++){
                    sum[i][j] += a[i][k]*b[k][j];
                }
            }

        }
    }
    public void ReadMatrix(String s){
        Scanner sc= new Scanner(s).useDelimiter("/n");

        ArrayList<ArrayList<Integer>> aValues = new ArrayList<ArrayList<Integer>>();
        ArrayList<ArrayList<Integer>> bValues = new ArrayList<ArrayList<Integer>>();
        aValues.clear();
        bValues.clear();

        while(sc.hasNext()) {
            String currentLine = sc.nextLine();

            // We have one line with one or more matrix rows
            // e.g. |1 2 3| |3 4|

            ArrayList<Integer> currentAValues = new ArrayList<Integer>();
            ArrayList<Integer> currentBValues = new ArrayList<Integer>();

            currentAValues.clear();
            currentBValues.clear();

            // See if we should add values to A or B
            //If A: line starts with "|"
            //If B: line starts with " "

            if (currentLine.charAt(0) == '|') {
                // Add values to A

                Boolean bStarted = false;
                int indexWhereBStarted = -1;
                String currentNum = "";

                for (int i = 1; i < currentLine.length(); i++) {

                    if (currentLine.charAt(i) != '|' && !bStarted) {
                        // Add to A

                        if ((currentLine.charAt(i) != ' ')) {

                            String currentChar = String.valueOf(currentLine.charAt(i));
                            currentNum += currentChar;
                            // currentAValues.add(Integer.parseInt(currentChar));
                        }
                        else {
                            // we have found a space
                            // currentNum has all digits
                            if (currentNum != "") {
                                currentAValues.add(Integer.parseInt(currentNum));
                                currentNum = "";
                            }
                        }
                    }
                    else {
                        if (bStarted == false) {
                            // Start adding to B
                            bStarted = true;
                            indexWhereBStarted = i;
                        }

                        // if the next char is also '|', then b started
                        if (currentLine.charAt(indexWhereBStarted+2) != '|') {
                            break;
                        }
                        else if (currentLine.charAt(i) != ' ' && currentLine.charAt(i) != '|') {
                            // add values to b
                            String currentChar = String.valueOf(currentLine.charAt(i));
                            currentBValues.add(Integer.parseInt(currentChar));
                        }
                    }
                }
            } // end check if A values present

            // In this case, only B values are present, e.g. " | 4 5 5 |"
            else if (currentLine.charAt(0) == ' ') {
                // Add values to B

                for (int i = 1; i < currentLine.length(); i++) {
                    if (currentLine.charAt(i) != '|' && (currentLine.charAt(i) != ' ')) {
                        // Add to B
                        String currentChar = String.valueOf(currentLine.charAt(i));
                        currentBValues.add(Integer.parseInt(currentChar));
                    }
                }
            }

            if (currentAValues != null && !currentAValues.isEmpty()) {
                aValues.add(currentAValues);
            }

            if (currentBValues != null && !currentBValues.isEmpty()) {
                bValues.add(currentBValues);
            }

        } // end for loop that processes entire line

        // At this point, we have 2d arrays in nested lists
        // need to translate them to 2d arrays
        a=new int[aValues.size()][aValues.get(0).size()];
        b=new int[bValues.size()][bValues.get(0).size()];

        for (int i=0; i< a.length;i++) {
            if (aValues.size() > 0) {
                for (int j=0; j<a[i].length; j++){
                    a[i][j]=aValues.get(i).get(j);
                }
            }
        }

        for (int i=0; i<b.length;i++) {
            if (bValues.size() > 0) {
                for (int j=0; j<b[i].length; j++){
                    b[i][j]=bValues.get(i).get(j);
                }
            }
        }
    }

    public static void main(String argc[]){
        MatrixMultiplication mm= new MatrixMultiplication();
        mm.ReadMatrix("| 10 2 3 | |  7  8 |\n"
                + "| 4 5 6 | |  9 10 |\n"
          + " | 11 12 |");
        mm.calculateSum(mm.a, mm.b);

        for (int i = 0; i < mm.sum.length; i++) {
            System.out.print("|");
            for (int j = 0; j < mm.sum[i].length; j++) {
                System.out.print(mm.sum[i][j] + " ");
            }
            System.out.print("|\n");
        }
    }
}