在树形图中设置树形图的值？

Question

请耐心等待我，我一整天都在网上搜索，试图找到正在发生的轻微问题的正确语法。如何在树形图中设置树形图？

地图的实例变量是：

    private final TreeMap<Integer,TreeMap<Integer,Double>> matrix;

/**
 * Change the value at a given position.
 * If the position is not in the matrix (i.e., i is not between 0 and rows-1
 * and j is not between 0 and cols-1), then don't change anything.
 *
 * @param i The row.
 * @param j The column.
 * @param v The new value.
 */
public void set(int i, int j, double v) {
    if (matrix.containsKey(i) && matrix.containsValue(j) == true) {
        matrix.remove(j); // Is this needed?
        matrix.put(i<j,v>); // ERROR: not right syntax for this 
    }
} // end of set method

Answer 1

这是你要找的吗？

matrix.get(i).put(j, v);

Answer 2

private final TreeMap<Integer,TreeMap<Integer,Double>> matrix;

您无法为声明为final的实例分配值，而不是在声明它的语句中：

public final TreeMap<Integer,TreeMap<Integer,Double>> matrix  = new TreeMap<>();

然后您应该像往常一样put get，TreeMap matrix：

matrix.put(1, new TreeMap<Integer, Double>());
matrix.get(1).put(1, 1.23);