算法练习五红黑树下节点删除

最新推荐文章于 2025-05-08 15:20:06 发布

原创最新推荐文章于 2025-05-08 15:20:06 发布 · 944 阅读

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#算法

本文介绍了一种实现红黑树节点删除的方法，包括删除操作及之后的平衡调整过程。通过使用辅助函数如查找最小元素、最大元素和后继节点等来完成整个删除流程。

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接着算法联系五，实现了红黑树的节点删除功能。

补充了五个函数，这里主要将删除和删除修正两个函数给出，其它的就十分简单了。

//删除

RBNode* RBDelete(RBNode** proot, RBNode* pnode, RBNode* pguardNode);

//删除修正

void RBDeleteFixup(RBNode** proot, RBNode* pnode, RBNode* pguardNode);

//返回以节点为根的最小元素

RBNode* TreeMinimum(RBNode* pnode, RBNode* pguardNode);

//返回以节点为根的最大元素

RBNode* TreeMaxmum(RBNode* pnode, RBNode* pguardNode);

//返回节点的后继

RBNode* TreeSuccessor(RBNode* pnode, RBNode* pguardNode);

//删除 RBNode* RBDelete(RBNode** proot, RBNode* pnode, RBNode* pguardNode) { RBNode* y; RBNode* x; if ( pnode->pLeft == pguardNode || pnode->pRight == pguardNode ) { y = pnode; } else { y = TreeSuccessor(pnode,pguardNode); } if ( y->pLeft != pguardNode ) { x = y->pLeft; } else { x = y->pRight; } x->pParent = y->pParent; if ( y->pParent == pguardNode ) { *proot = x; } else { if ( y == y->pParent->pLeft ) { y->pParent->pLeft = x; } else { y->pParent->pRight = x; } } if ( y != pnode ) { pnode->key = y->key; //*这里没有将y的颜色赋值给pnode，这一点十分重要*// } if ( y->color == BLACK ) { RBDeleteFixup( proot,x,pguardNode ); } return y; } //删除修正 void RBDeleteFixup(RBNode** proot, RBNode* px, RBNode* pguardNode) { RBNode* w; while( px != *proot && px->color == BLACK && px != pguardNode ) { if ( px == px->pParent->pLeft ) //case1 px的兄弟是红色的 { w = px->pParent->pRight; if ( w->color == RED ) { w->color = BLACK; px->pParent->color = RED; LeftRotate( proot, px->pParent, pguardNode ); w = px->pParent->pRight; } if ( w->pLeft->color == BLACK && w->pRight->color == BLACK ) { // case2 px的兄弟w是黑色的，并且w的两个孩子都是黑色的 w->color = RED; px = px->pParent; } else { if ( w->pRight->color == BLACK ) { //case3 px的兄弟w是黑色的,w的左孩子是红色的，右孩子是黑色的 w->pLeft->color = BLACK; w->color = RED; RightRotate(proot,w,pguardNode); w = px->pParent->pRight; } w->color = px->pParent->color; px->pParent->color = BLACK; w->pRight->color = BLACK; LeftRotate(proot,px->pParent,pguardNode); px = *proot; } } else // px == px->pParent->pRight { w = px->pParent->pLeft; if ( w->color == RED ) { w->color = BLACK; px->pParent->color = RED; RightRotate( proot, px->pParent, pguardNode ); w = px->pParent->pLeft; } if ( w->pLeft->color == BLACK && w->pRight->color == BLACK ) { w->color = RED; px = px->pParent; } else { if ( w->pLeft->color == BLACK ) { w->pRight->color = BLACK; w->color = RED; LeftRotate( proot, w, pguardNode ); w = px->pParent->pLeft; } w->color = px->pParent->color; px->pParent->color = BLACK; w->pLeft->color = BLACK; RightRotate(proot, px->pParent, pguardNode ); px = *proot; } } }//end while loop px->color = BLACK; }