// Arup Guha
// 4/24/2016
// Framework for 2015 AP CS A Free Response Question 3: Sparse Array Storage

import java.util.*;

public class SparseArray {

	private int numRows;
	private int numCols;
	private List<SparseArrayEntry> entries;

	/*** Note: The AP People messed up here. In their example, their array was a 6 x 5, but had all 0s in rows 4 and 5. If you create an empty
	 *         one of these, like they had and then change numRows and numCols dynamically after each entry add and deletion, then for their
	 *         example, the array would be size 4 x 5 then 4 x 4. But, they wanted it to be 6 x 5. This indicates to me that these values HAVE
	 *         to be set independently of the actual non-zero entries. So, I just put them in the constructor...
	 ***/
	public SparseArray(int rows, int cols) {
		entries = new ArrayList<SparseArrayEntry>();
		numRows = rows;
		numCols = cols;
	}

	public int getNumRows() {
		return numRows;
	}

	public int getNumCols() {
		return numCols;
	}

	public void addEntry(SparseArrayEntry e) {
		entries.add(e);
	}

	/*** Fill in your solution to part A here. ***/
	public int getValueAt(int row, int col) {

	}

	/*** Fill in your solution to part B here. ***/
	public void removeColumn(int col) {

	}

	// Just for testing.
	public String toString() {
		String res = "Array is "+numRows+" x "+numCols+"\n";
		for (int i=0; i<entries.size(); i++)
			res = res + entries.get(i) + "\n";
		return res;
	}

	// Just the test on the test.
	public static void main(String[] args) {
		SparseArray arr = new SparseArray(6, 5);
		arr.addEntry(new SparseArrayEntry(2, 0, 1));
		arr.addEntry(new SparseArrayEntry(1, 1, 5));
		arr.addEntry(new SparseArrayEntry(3, 1, -9));
		arr.addEntry(new SparseArrayEntry(1, 4, 4));
		System.out.println("The original array:");
		System.out.println(arr);
		arr.removeColumn(1);
		System.out.println("New array is:");
		System.out.println(arr);
	}
}

// Made default and not public since I wanted to code the whole solution in one file. This is their included class.
class SparseArrayEntry {

	private int row;
	private int col;
	private int value;

	public SparseArrayEntry(int r, int c, int v) {
		row = r;
		col = c;
		value = v;
	}

	public int getRow() {
		return row;
	}

	public int getCol() {
		return col;
	}

	public int getValue() {
		return value;
	}

	public String toString() {
		return "A["+row+"]["+col+"] = "+value;
	}
}