poj1577

排序二叉树

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#include <iostream>

#include <cstdlib>

#include <cstdio>

#include <cstring>

using namespace std;



#define maxn 105



struct Node

{

    Node *left, *right;

    char letter;

}tree[maxn];



char st[maxn];

int node_cnt;



void insert(Node * &proot, char ch)

{

    if (proot == NULL)

    {

        proot = &tree[node_cnt++];

        proot->left = NULL;

        proot->right = NULL;

        proot->letter = ch;

        return;

    }

    if (ch > proot->letter)

        insert(proot->right, ch);

    else

        insert(proot->left, ch);



}



void output(Node *proot)

{

    putchar(proot->letter);

    if (proot->left)

        output(proot->left);

    if (proot->right)

        output(proot->right);

}



void input()

{

    char *p = st;

    while (1)

    {

        scanf("%s", p);

        if (*p == '*')

            return;

        if (*p == '$')

            return;

        p = st + strlen(st);    

    }

}



int main()

{

    //freopen("t.txt", "r", stdin);

    while (1)

    {

        input();

        Node *proot = NULL;

        node_cnt = 0;

        for (int i = strlen(st) - 2; i >= 0; i--)

            insert(proot, st[i]);

        output(proot);

        putchar('\n');

        if (st[strlen(st) - 1] == '$')

            break;

    }

    return 0;

}