寒假集训——二叉树

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#include <iostream>#include <stdio.h>#include <string.h>#include <queue>using namespace std;typedef struct node{    char date;    node *lch,*rch;}Bn,*Bt;void cbtree(Bt &T)//先序建二叉树{    char c;    scanf("%c",&c);    if(c==',')        T=NULL;    else{        T=new Bn;        T->date=c;        cbtree(T->lch);        cbtree(T->rch);    }    return ;}void pre(Bt T)//先序遍历二叉树{    if(T)    {        printf("%c",T->date);        pre(T->lch);        pre(T->rch);    }}void in(Bt T)//中序遍历二叉树{    if(T)    {        in(T->lch);        printf("%c",T->date);        in(T->rch);    }}void post(Bt T)//后序遍历二叉树{    if(T)    {        post(T->lch);        post(T->rch);        printf("%c",T->date);    }}void level(Bt T)//层次遍历二叉树{    queue<Bn>Q;    Q.push(*T);    while(!Q.empty())    {        Bn next=Q.front();        Q.pop();        printf("%c",next.date);        if(next.lch)Q.push(*(next.lch));        if(next.rch)Q.push(*(next.rch));    }}int cnt=0;void cntleaf1(Bt T)//求叶子节点{    if(T)    {        if(!T->lch&&!T->rch)        {            cnt++;            return;        }        cntleaf1(T->lch);        cntleaf1(T->rch);    }}int cntleaf2(Bt T)//求叶子节点{    if(!T)return 0;    if(!T->lch&&!T->rch)return 1;    else    {        int nl=cntleaf2(T->lch);        int nr=cntleaf2(T->rch);        return nl+nr;    }}int dep(Bt T)//求二叉树的深度{    int ddep=0;    if(!T) return ddep;    int nl=dep(T->lch);    int nr=dep(T->rch);    return (nl>nr?nl:nr)+1;}int main(){    Bt head;    //先序建二叉树    cbtree(head);    //先序遍历二叉树    pre(head);    printf("\n");    //中序遍历二叉树    in(head);    printf("\n");    //后序遍历二叉树    post(head);    printf("\n");    //层次遍历二叉树    level(head);    printf("\n");    //求二叉树的叶子节点    cntleaf1(head);    printf("%d\n",cnt);    printf("%d\n",cntleaf2(head));    //求二叉树深度    printf("%d\n",dep(head));}

#include <iostream>#include <stdio.h>#include <string.h>#include <queue>using namespace std;typedef struct node{    char date;    node *lch,*rch;}Bn,*Bt;char pre[1000],ins[1000],post[1000];void cbtree1(Bt &T,char *pre,char *ins,int n)//根据先序和中序建立二叉树{    if(n<=0)T=NULL;    else    {        int k=strchr(ins,pre[0])-ins;        T=new Bn;        T->date=pre[0];        cbtree1(T->lch,pre+1,ins,k);        cbtree1(T->rch,pre+k+1,ins+k+1,n-k-1);    }}void cbtree2(Bt &T,char *ins,char *post,int n)//根据中序和后序建立二叉树{    if(n<=0)T=NULL;    else    {        int k=strchr(ins,post[n-1])-ins;        T=new Bn;        T->date=post[n-1];        cbtree2(T->lch,ins,post,k);        cbtree2(T->rch,ins+k+1,post+k,n-k-1);    }}void preorder(Bt &T)//先序遍历二叉树{    if(T)    {        printf("%c",T->date);        preorder(T->lch);        preorder(T->rch);    }}void postorder(Bt &T)//后序遍历二叉树{    if(T)    {        postorder(T->lch);        postorder(T->rch);        printf("%c",T->date);    }}int main(){    Bt head;    scanf("%s%s",pre,ins);//先序和中序    cbtree1(head,pre,ins,strlen(pre));    postorder(head);    //scanf("%s%s",ins,post);//中序和后序    //cbtree2(head,ins,post,strlen(post));    //preorder(head);}

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