第十四届蓝桥杯集训——练习解题阶段(无序阶段)-ALGO-682 求先序排列

#include"stdio.h"  
 #include"string.h"  
 void dg(char z[],char h[])  
 {  
     if(strlen(h)==0)  
         return;  
     printf("%c",h[strlen(h)-1]);  
     if(strlen(h)==1)  
         return;  
     if(strlen(h)==2)  
     {  
         printf("%c",h[0]);  
         return;  
    }  
     char a[9],b[9];  
     int i,j;  
    for(i=0;z[i]!=h[strlen(h)-1];i++)  
        a[i]=z[i],b[i]=h[i];  
     a[i]='\0';  
     b[i++]='\0';  
     dg(a,b);  
     for(j=0;i<strlen(h);i++,j++)  
         a[j]=z[i],b[j]=h[i-1];  
     a[j]='\0';  
     b[j]='\0';  
     dg(a,b);  
 }  
 int main()  
 {  
     char h[9],z[9];  
     scanf("%s",z);  
    scanf("%s",h);  
    dg(z,h);  
     return 0;  
 }

#include<iostream>
#include<algorithm>
#include<string>
using namespace std;
string a, b;
void before( int hl, int hr,int zl, int zr)
{
    if (zl == zr) {
        return;
    }
    int flag=-1;
    for (int i = 0; i < zr; i++) {
        if (a[i] == b[hr - 1]) {
            flag = i;
            cout << a[flag];
            break;
        }
    }
     before( hl, hl  + flag- zl,zl, flag);        //左子树
     before(hl+ flag - zl, hr - 1,flag + 1, zr);  //右子树
}
int main()
{
    cin >> a >> b;
    before( 0, b.length(),0, a.length());
}

import java.util.Arrays;
import java.util.Scanner;
public class Main {
    public static void main(String[] args) {
        Scanner s=new Scanner(System.in);
        String zhong=s.nextLine();
        String hou=s.nextLine();
        dfs(zhong,hou);
    }
    private static void dfs(String zhong, String hou) {
        char node=hou.charAt(hou.length()-1);
        System.out.print(node);
        int midnode_index=zhong.indexOf(node);
        if (midnode_index>0){
            dfs(zhong.substring(0,midnode_index),hou.substring(0,midnode_index));
        }if (midnode_index<zhong.length()-1){
            dfs(zhong.substring(midnode_index+1),hou.substring(midnode_index,hou.length()-1));
        }
    }
}

class TreeNode(object):
    def __init__(self,x):
        self.val = x
        self.left = None
        self.right = None
def post(root,ans):
    if not root:
        return
    
    ans.append(root.val)
    post(root.left,ans)
    post(root.right,ans)
def f(zhong,hou):
    if len(zhong) == 0:
        return None
    
    x = hou[-1]
    node = TreeNode(x)
    i = zhong.index(x)
    
    zhong_right = zhong[i + 1:]
    zhong_left = zhong[:i]
    
    k = -1 - len(zhong_right)
    hou_right = hou[k:-1]
    hou_left = hou[:len(zhong_left)]
    
    node.left = f(zhong_left,hou_left)
    node.right = f(zhong_right,hou_right)
    
    return node
    
zhong = input()
hou = input()
root = f(zhong,hou)
ans = []
post(root,ans)
for t in ans:
    print(t,end='')