递归路径方法

Question

我一直致力于设计一个代码，用于在2D数组中打印出“运动总和”。 我得到了一个带有正整数的矩阵用于条目，具有起始位置NW并且它应该在SE结束，并且对于每个这样的路径，我被要求该路径的总权重（相关条目的“总和”）。 为了使事情更清楚，我要求记录下面的任何步骤。 问题是，我没有错误，但方法的第一步是错误的 - 它总是首先上升。我不知道哪一步让它发生了。你能发现任何错误吗？

public class question02
{
    public static void printPathWeights(int [][] m)
    {
        pathing (m, 0, 0, 0);
    }
    private static void pathing (int [] [] m , int currH , int currV , int value)
    {
        if ( validPath( m , currH - 1 , currV ) == true ) //up
        {
            value += m[currH][currV];
            int tmp = m[currH][currV];
            m[currH][currV] = -1;
            System.out.println ("going up");
            pathing ( m , currH - 1, currV , value );
            m[currH][currV] = tmp;
        }
        if ( validPath( m , currH + 1 , currV ) == true ) //down
        {
            value += m[currH][currV];
            int tmp = m[currH][currV];
            m[currH][currV] = -1;
            System.out.println ("going down");
            pathing ( m , currH + 1, currV , value );
            m[currH][currV] = tmp;
        }
        if ( validPath( m , currH , currV - 1 ) == true ) //left
        {
            value += m[currH][currV];
            int tmp = m[currH][currV];
            m[currH][currV] = -1;
            System.out.println ("going left");
            pathing ( m , currH , currV - 1 , value );
            m[currH][currV] = tmp;
        }
        if ( validPath( m , currH , currV + 1 ) == true ) //right
        {
            value += m[currH][currV];
            int tmp = m[currH][currV];
            m[currH][currV] = -1;
            System.out.println ("going right");
            pathing ( m , currH , currV + 1 , value );
            m[currH][currV] = tmp;
        }
        if ( currH == m.length -1 && currV == m[0].length -1 ) //end
        {
            System.out.println (value);
        }
    }
    private static boolean validPath (int [] [] m , int possH , int possV )
    {
        if ( ( possH < 0 ) || ( possH >= m.length - 1 ) || ( possV < 0 ) || ( possV >= m[0].length - 1 ) )
        {
            return false;
        }
        if (m[possH][possV] == -1)
        {
            return false;
        }
        else return true;
    }
}