sparsematrix.java

用hashmap实现查找,存储等功能 定义了一个接口,并用稀疏矩阵实现

package shuli;

import java.text.NumberFormat;
import java.util.Vector;

public class SparseMatrix implements Matrix{
	private Object matrix[][] = null;
	
	public SparseMatrix(int row,int col){
		matrix = new Object[row][col];
	}

	public Object get(int i, int j) {
		return matrix[i][j];
	}

	public void put(int i, int j, Object value) {
		matrix[i][j] = value;
		
	}

	public Vector multiply(Vector v) {
		Vector result = new Vector();
		double temp = 0;
		for(int i = 0; i < matrix.length; i++){
			for(int j = 0; j < matrix[i].length; j++){
				if(matrix[i][j] != null)
					temp +=  ((Number)matrix[i][j]).intValue() *  ((Number)v.get(j)).intValue();
			}
			result.add(i,new Double(temp));
			temp = 0;
		}
			
		return result;
	}

	public String toString(String emptyValue) {
		String result = "";
		for(int i = 0;i < matrix.length; i++){
			for(int j = 0; j < matrix[i].length;j++){
				if(matrix[i][j] == null){
					if(j!=0)
						result += ",";
					result += "0";
				}
				else{
					if(j!=0)
						result += ",";
					
					result += ((Number)matrix[i][j]).intValue();
				}
			}
			result += "\n";
		}
		
		return result;
	}

}