《入门经典》2

来源：互联网发布：python 判断加载完成编辑：程序博客网时间：2024/06/08 11:37
#include <iostream>#include <cstdio>#include <cstring>#include <cstdlib>#include <queue>#include <vector>#define maxn 20struct node{    int value;    bool have_value;    node *left,*right;    node():value(0),have_value(false),left(NULL),right(NULL){}};using namespace std;char s[maxn];node *root;bool failed;node nodes[256];queue<node*>pool;void minit(){    int i;    for(i=0;i<256;++i)        pool.push(&nodes[i]);}node*newnode(){    node *a = pool.front();    pool.pop();    a -> left = a -> right = 0;    a -> have_value = false;    return a;}void addnode(int value,char *s){    int i=0,n=strlen(s);    node *u = root;    for(;i<n;++i)    {        if(s[i] == 'L')        {            if(u -> left == NULL)                u -> left = newnode();            u = u->left;        }        if(s[i] == 'R')        {            if(u -> right == NULL)                u -> right = newnode();            u = u->right;        }    }    if(u -> have_value) failed = true;    u -> value = value;    u -> have_value = true;}bool read_input(){    failed = false;    root = newnode();    for(;;)    {        if(scanf("%s",s)!=1)            return false;        if(!strcmp(s,"()"))            break;        int v;        sscanf(&s[1],"%d",&v);        addnode(v,strchr(s,',')+1);    }    return true;}void pre_dfs(vector<int> &pre_ans,node *u)//先序{    pre_ans.push_back(u -> value);    if(u -> left != NULL)        pre_dfs(pre_ans,u -> left);    if(u -> right != NULL)        pre_dfs(pre_ans,u -> right);}void in_dfs(vector<int> &in_ans,node *u)//中序{    if(u -> left != NULL)        in_dfs(in_ans,u -> left);    in_ans.push_back(u -> value);    if(u -> right != NULL)        in_dfs(in_ans,u -> right);}void post_dfs(vector<int> &post_ans,node *u)后序{    if(u -> left != NULL)        post_dfs(post_ans,u -> left);    if(u -> right != NULL)        post_dfs(post_ans,u -> right);    post_ans.push_back(u -> value);}int main(){    minit();    vector<int> pre_ans;    pre_ans.clear();    vector<int> in_ans;    in_ans.clear();    vector<int> post_ans;    post_ans.clear();    read_input();    pre_dfs(pre_ans,root);    in_dfs(in_ans,root);    post_dfs(post_ans,root);    size_t i;    for(i=0;i<pre_ans.size();++i)        printf("%d ",pre_ans[i]);    printf("\n");    for(i=0;i<in_ans.size();++i)        printf("%d ",in_ans[i]);    printf("\n");    for(i=0;i<post_ans.size();++i)        printf("%d ",post_ans[i]);    printf("\n");    return 0;}
二叉树 DFS 先序中序后序
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