/// <summary>
/// Reconstruct connected node a,b,c and their childrens.
/// 将相连的三个顶点和其子孙连进行重构
/// </summary>
/// <returns>新的祖先，即<paramref name="b"/></returns>
/// <remarks>
/// after reconstruction:
/// 重构以后的形状
/// b
/// / \
/// a c
/// / \ / \
/// t0 t1 t2 t3
/// </remarks>
protected static BinaryTreeNode Connect34(BinaryTreeNode a, BinaryTreeNode b, BinaryTreeNode c, BinaryTreeNode t0, BinaryTreeNode t1, BinaryTreeNode t2, BinaryTreeNode t3, BinaryTreeNode top)
{
Contract.Requires <ArgumentNullException>(a != null);
Contract.Requires <ArgumentNullException>(b != null);
Contract.Requires <ArgumentNullException>(c != null);
Contract.Ensures(a.LeftChild == t0);
Contract.Ensures(a.RightChild == t1);
Contract.Ensures(c.LeftChild == t2);
Contract.Ensures(c.RightChild == t3);
Contract.Ensures(b.LeftChild == a);
Contract.Ensures(b.RightChild == c);
Contract.EndContractBlock();
top.TransferParent(b);
a.LeftChild = t0;
a.RightChild = t1;
a.SearchUp(true);
c.LeftChild = t2;
c.RightChild = t3;
c.SearchUp(true);
b.LeftChild = a;
b.RightChild = c;
b.SearchUp();
return(b);
}
