public static int Cmp(ZZeroNode a, ZZeroNode b)
{
return(a.ZeroNum.CompareTo(b.ZeroNum));
}
/// <summary>
/// 檢驗各列，對碰上之第一個零，做記號，同列或同欄的其他零則畫X (由零較少的列先做，可不依順序)
///
/// 檢驗可否完成僅含零的完全指派，若不能，則false
/// </summary>
private bool step2()
{
_result.Clear();
bool[,] isDelete = new bool[_x, _y];
//零的数量由少到多
List <ZZeroNode> zeroNodes = new List <ZZeroNode>();
for (int x = 0; x < _x; x++)
{
int zeroNum = 0;
for (int y = 0; y < _y; y++)
{
if (_data[x, y] == 0)
{
zeroNum++;
}
}
if (zeroNum > 0)
{
zeroNodes.Add(new ZZeroNode(x, zeroNum));
}
}
zeroNodes.Sort(ZZeroNode.Cmp);
//从零较少的行开始
while (zeroNodes.Count > 0)
{
ZZeroNode node = zeroNodes[0];
if (node.ZeroNum <= 0)
{
zeroNodes.RemoveAt(0);
}
else
{
for (int y = 0; y < _y; y++)
{
if (_data[node.X, y] == 0 && !isDelete[node.X, y])
{
_result.Add(new Point(node.X, y));
zeroNodes.RemoveAt(0);
//删除与该零在同一列的其他零
for (int xxx = 0; xxx < _x; xxx++)
{
if (_data[xxx, y] == 0)
{
isDelete[xxx, y] = true;
for (int i = 0; i < zeroNodes.Count; i++)
{
if (zeroNodes[i].X == xxx)
{
zeroNodes[i].ZeroNum--;
}
}
}
}
break;
}
}
}
zeroNodes.Sort(ZZeroNode.Cmp);
}
return(_result.Count == _x);
}
