import?java.util.ArrayList;
import?java.util.List;

public?class?Matrix?{
	private?String[][]?data;

	public?Matrix（String[][]?data）?{
		int?r?=?data.length;
		int?c?=?data[0].length;
		this.data?=?new?String[r][c];
		for?（int?i?=?0;?i?			for?（int?j?=?0;?j?				this.data[i][j]?=?data[i][j];
			}
		}
	}

	/*
	?*?convenience?method?for?getting?a?string?representation?of?matrix
	?*/
	public?String?toString（）?{
		StringBuilder?sb?=?new?StringBuilder（1024）;
		for?（String[]?row?:?this.data）?{
			for?（String?val?:?row）?{
				sb.append（val）;
				sb.append（“?“）;
			}
			sb.append（“\n“）;
		}

		return?（sb.toString（））;
	}

	public?void?removeRow（final?int?index）?{
		/*
		?*?Use?an?array?list?to?track?of?the?rows?we‘re?going?to?want?to
		?*?keep...arraylist?makes?it?easy?to?grow?dynamically?so?we?don‘t?need
		?*?to?know?up?front?how?many?rows?we‘re?keeping
		?*/
		List?rowsToKeep?=?new?ArrayList（this.data.length）;
		for?（String[]?row?:?this.data）?{
			rowsToKeep.add（row）;

		}
		rowsToKeep.remove（index）;
		/*
		?*?now?that?we?know?what?rows?we?want?to?keep?make?our?new?2D?array
		?*?with?only?those?rows
		?*/
		this.data?=?new?String[rowsToKeep.size（）][];
		for?（int?i?=?0;?i?