public static Output TraverseMatrixFromBack(Helfer.Matrix <int> mat)
{
for (int index = mat.Length - 2; index >= 0; index--)
{
int botEl = mat.GetRow(index) == mat.RowNum - 1 ? int.MaxValue : mat.GetElement(mat.GetRow(index) + 1, mat.GetCol(index)); // If LAST ROW: int.Max ELSE: take bottom element
int rightEl = mat.GetCol(index) == mat.ColNum - 1 ? int.MaxValue : mat.GetElement(mat.GetRow(index), mat.GetCol(index) + 1); // If LAST COL: int.Max ELSE: take right element
mat.SetElementAtIndex(index, mat.GetElementAtIndex(index) + Math.Min(botEl, rightEl)); // Add smaller accumulated element to current
// This means it goes along the path with the smaller sum
// The smaller sum accumulates along the path
}
Helfer.Point[] trace = new Helfer.Point[mat.RowNum + mat.ColNum - 1];
for (int ind = 0, ptTrace = 0; ptTrace < trace.Length;)
{
trace[ptTrace++] = new Helfer.Point(mat.GetRow(ind), mat.GetCol(ind));
int botEl = mat.GetRow(ind) == mat.RowNum - 1 ? int.MaxValue : mat.GetElement(mat.GetRow(ind) + 1, mat.GetCol(ind));
int rightEl = mat.GetCol(ind) == mat.ColNum - 1 ? int.MaxValue : mat.GetElement(mat.GetRow(ind), mat.GetCol(ind) + 1);
if (botEl < rightEl)
{
ind = mat.EncodePos(mat.GetRow(ind) + 1, mat.GetCol(ind));
}
else
{
ind = mat.EncodePos(mat.GetRow(ind), mat.GetCol(ind) + 1);
}
}
return(new Output(mat.GetElementAtIndex(0), trace, mat.mat));
}
public static Output TraverseMatrixFromBack_WithoutExtraMethods(int[,] mat)
{
for (int index = mat.Length - 2; index >= 0; index--)
{
int col = index % mat.GetLength(1);
int row = index / mat.GetLength(1);
int botEl = row == mat.GetLength(0) - 1 ? int.MaxValue : mat[row + 1, col]; // If LAST ROW: int.Max ELSE: take bottom element
int rightEl = col == mat.GetLength(1) - 1 ? int.MaxValue : mat[row, col + 1]; // If LAST COL: int.Max ELSE: take right element
mat[row, col] += Math.Min(botEl, rightEl); // Add smaller accumulated element to current
// This means it goes along the path with the smaller sum
// The smaller sum accumulates along the path
}
Helfer.Point[] trace = new Helfer.Point[mat.GetLength(0) + mat.GetLength(1) - 1];
for (int ind = 0, ptTrace = 0; ptTrace < trace.Length;)
{
int col = ind % mat.GetLength(1);
int row = ind / mat.GetLength(1);
trace[ptTrace++] = new Helfer.Point(row, col);
int botEl = row == mat.GetLength(0) - 1 ? int.MaxValue : mat[row + 1, col];
int rightEl = col == mat.GetLength(1) - 1 ? int.MaxValue : mat[row, col + 1];
if (botEl < rightEl)
{
ind = (row + 1) * mat.GetLength(1) + col;
}
else
{
ind = row * mat.GetLength(1) + col + 1;
}
}
return(new Output(mat[0, 0], trace, mat));
}
