求后序遍历

 1 #include <iostream>
 2 #include <string>
 3 using namespace std;
 4 
 5 string s1="abdec";//先序遍历
 6 string s2="dbeac";//中序遍历
 7 
 8 void calc(int l1,int r1,int l2,int r2){
 9     int m=s2.find(s1[l1]);
10     //cout<<m<<endl;
11     if(m>l2) calc(l1+1,l1+m-l2,l2,m-1);
12     if(m<r2) calc(l1+m-l2+1,r1,m+1,r2);
13     //cout<<s2[m]<<" ";
14     cout<<s1[l1];
15 } 
16 
17 int main(){
18     
19     calc(0,s1.length()-1,0,s2.length()-1); 
20     cout<<endl;
21     return 0;
22 }