#codingexercise
In a rowwise and columnwise sorted matrix, enumerate the elements in ascending order

There is a front that moves from the top left corner to the bottom right. Element along the front are guaranteed to include the minimum. Since the front only moves one cell down or to the right, the element along the zig zag shape of the front are easy to enumerate to pick out the minimum at any step.

void PrintSerialized(int[ , ] A, int rows, int cols)

{

if ( A== null || rows == 0 || cols == 0) return;

var items = new List<Tuple<int,int>>();

items.Add(new Tuple<int,int>(0,0));

while ( items.Count != 0 )

{

// print current min

var item = RemoveMinValue(items);

Console.WriteLine(item.GetValue());

// add next candidates

var down = new Tuple<int,int>(item.first+1, item.second);

var right = new Tuple<int,int>(item.first,item.second+1);

if (IsValid(down) && items.Contains(down) == false)

    items.Add(down);

if (IsValid(right) && items.Contains(right) == false)

    items.Add(right);

}

Console.WriteLine(A[r,c]);

}

5  10   12  14

6  11  13   19

7  15  22  29

9  25  32  39