标签：style blog http io ar color os sp for
二叉树先序后序中序的重建与遍历：
ZOJ1944 已知前序和中序求后序
不建树版
#include<iostream> #include<cstdio> #include<cstring> using namespace std; char pre[30],in[30]; int num; void Postorder(int l,int r) { if(l>r)return ; if(l==r){ num++; printf("%c",in[l]); return; } int re=l; for(int i=l;i<=r;i++) { if(in[i]==pre[num]){ re=i; break; } } num++; Postorder(l,re-1); Postorder(re+1,r); printf("%c",in[re]); } int main() { int n; while(~scanf("%s%s",pre,in)) { num=0; Postorder(0,strlen(pre)-1); printf("\n"); } return 0; }
建树版
#include<iostream> #include<cstdio> #include<cstring> using namespace std; char pre[30],in[30]; struct node { char value; node *left,*right; }; int num; node* Build(int l,int r) { // printf("%d %d %d\n",num,l,r); node* root=new node; root->value=pre[num]; if(l>r)return NULL; if(l==r){ num++; root->left=NULL; root->right=NULL; return root; } int i; int re=l; for(i=l;i<=r;i++) { if(in[i]==pre[num]){ re=i; break; } } num++; root->left=Build(l,re-1); root->right=Build(re+1,r); return root; } void Put_data(node *root) { if(root->left!=NULL)Put_data(root->left); if(root->right!=NULL)Put_data(root->right); printf("%c",root->value); } int main() { int n; while(~scanf("%s%s",pre,in)) { num=0; node* root=Build(0,strlen(in)-1); Put_data(root); printf("\n"); } return 0; }
Pat1086先序建树，后序输出
#include<iostream> #include<cstdio> #include<algorithm> using namespace std; struct Node{ int value; Node *leftChild; Node *rightChild; Node(int v):value(v),leftChild(NULL),rightChild(NULL){} }; char ch[10]; int n,num; int flag; Node* Build(Node* root) { if(num>=2*n)return NULL; scanf("%s",ch); if(ch[1]==‘u‘){ root=new Node(0); scanf("%d",&root->value); num++; root->leftChild=Build(root->leftChild); root->rightChild=Build(root->rightChild); } else { root=NULL; num++; } return root; } void PutTree(Node *root) { if(root!=NULL){ PutTree(root->leftChild); PutTree(root->rightChild); if(!flag){ printf("%d",root->value); flag=1; } else printf(" %d",root->value); } } int main() { while(~scanf("%d",&n)) { Node *root=NULL; num=0; flag=0; root=Build(root); PutTree(root); puts(""); } return 0; }
Pat1043二叉搜索树
#include <iostream> using namespace std; int flag; //是否符合条件标志位，0符合，1不符合 struct node //树中的点 { int value; //值 node *left,*right; //左右子树 }; node* Build1(int *data,int p,int q) //数据，起始、终止位置[p,q]; { if(p>q) return NULL; if(flag==1) //不符合条件，直接跳出（应该放到最前） return NULL; node* root=new node; root->value=data[p]; if(p==q) //只有一个数 { root->left=NULL; root->right=NULL; return root; } int i; int r=p; //第一个比data[p]大的数 for(i=p+1;i<=q;i++) { if(data[i]>=data[p]) { r=i; break; } } if(r>p) //找得到比data[p]大的data[r] { for(i=r+1;i<=q;i++) { if(data[i]<data[p]) { flag=1; return NULL; } } root->left=Build1(data,p+1,r-1); root->right=Build1(data,r,q); } else //找不到 { root->left=Build1(data,p+1,q); root->right=NULL; } return root; } node* Build2(int *data,int p,int q) //镜像 { if(p>q) return NULL; if(flag==1) return NULL; node* root=new node; root->value=data[p]; if(p==q) { root->left=NULL; root->right=NULL; return root; } int i; int r=p; for(i=p+1;i<=q;i++) { if(data[i]<data[p]) //注意镜像的定义 { r=i; break; } } if(r>p) { for(i=r+1;i<=q;i++) { if(data[i]>=data[p]) { flag=1; return NULL; } } root->left=Build2(data,p+1,r-1); root->right=Build2(data,r,q); } else { root->left=Build2(data,p+1,q); root->right=NULL; } return root; } int put_flag=0; //是否输出过信息标志位，用于跳过第一个空格 void Put_data(node *root) { if(root->left!=NULL) Put_data(root->left); if(root->right!=NULL) Put_data(root->right); if(put_flag==1) cout<<" "; else put_flag=1; cout<<root->value; } int main() { int n,data[1001]; //数据 int i; cin>>n; for(i=0;i<n;i++) cin>>data[i]; if(n==1) //只有一个值，符合条件 { cout<<"YES\n"; cout<<data[0]; return 0; } flag=0; //考虑正向 node *root=Build1(data,0,n-1); if(flag==0) { cout<<"YES\n"; Put_data(root); return 0; } flag=0; //考虑镜像 root=Build2(data,0,n-1); if(flag==0) { cout<<"YES\n"; Put_data(root); } else //都不符合 cout<<"NO"; return 0; }
Pat 1066 平衡二叉树的旋转插入
http://blog.csdn.net/tiantangrenjian/article/details/12891091
#include<iostream> #include<cstdio> #include<algorithm> using namespace std; struct Node { int value; int height; Node *leftChild; Node *rightChild; Node(int v):value(v),leftChild(NULL),rightChild(NULL),height(0){} }; int getHeight(Node *node) { if(node == NULL)return -1; return node->height; } bool isBalance(Node* parent) { return abs(getHeight(parent->leftChild)-getHeight(parent->rightChild))<2; } Node* rotate_LL(Node* parent) { Node* child=parent->leftChild; parent->leftChild=child->rightChild; child->rightChild=parent; parent->height = max(getHeight(parent->leftChild),getHeight(parent->rightChild))+1; child->height = max(getHeight(child->leftChild),getHeight(child->rightChild))+1; return child; } Node* rotate_RR(Node* parent) { Node* child=parent->rightChild; parent->rightChild=child->leftChild; child->leftChild=parent; parent->height = max(getHeight(parent->leftChild),getHeight(parent->rightChild))+1; child->height = max(getHeight(child->leftChild),getHeight(child->rightChild))+1; return child; } Node* rotate_LR(Node* parent) { Node* child=parent->leftChild; parent->leftChild=rotate_RR(child); return rotate_LL(parent); } Node* rotate_RL(Node *parent) { Node* child=parent->rightChild; parent->rightChild=rotate_LL(child); return rotate_RR(parent); } Node* InsertNode(Node* root,int newValue) { if(root!=NULL) { if(newValue>root->value) { root->rightChild=InsertNode(root->rightChild,newValue); if(!isBalance(root)) { if(newValue>root->rightChild->value) { root=rotate_RR(root); } else root=rotate_RL(root); } } else { root->leftChild=InsertNode(root->leftChild,newValue); if(!isBalance(root)) { if(newValue>root->leftChild->value) root=rotate_LR(root); else root=rotate_LL(root); } } } else{ root=new Node(newValue); } root->height=max(getHeight(root->leftChild),getHeight(root->rightChild))+1; return root; } int main() { int n; while(~scanf("%d",&n)) { int val; Node *root=NULL; for(int i=0;i<n;i++) { scanf("%d",&val); root=InsertNode(root,val); } printf("%d\n",root->value); } return 0; }
标签：style blog http io ar color os sp for
原文地址：http://www.cnblogs.com/kylehz/p/binary_tree.html
