2015 #3 part b

Solution.java

public void removeCol(int col) {
    for (int i = entries.size() - 1; i >= 0; i--) {
        SparseArrayEntry entry = entries.get(i);
        if (entry.getCol() > col) {
            // Fix the column number for this item because it's in a column
            // to the right of the column we're removing
            SparseArrayEntry fixedEntry = new SparseArrayEntry(entry.getRow(),
                                                               entry.getCol() - 1,
                                                               entry.getValue());
            entries.set(i, fixedEntry);
        }
        else if (entry.getCol() == col) {
            // Remove this item because it's inside the column we're removing
            entries.remove(i);
        }
    }

    // Update the numCols variable since we removed one column.
    numCols--;
}