ZOJ(1004)Anagrams by Stack (DFS+stack)

#include <iostream>
#include <stdio.h>
#include <string>
#include <string.h>
#include <algorithm>
#include <math.h>
#include <fstream>
#include <vector>
#include <map>
#include <queue>
#include <stack>
#include <math.h>
#include <stdlib.h>
using namespace std ;
string origion,target;
stack<char>build;
vector<char>operate;
int length;
void dfs(int ipush,int ipop){
    if(ipush == length&&ipop == length){
        for(int i = 0;i < operate.size();i++)
            cout<<operate[i]<<" ";
        cout<<endl;
    }
    if(ipush+1<=length){
        build.push(origion[ipush]);
        operate.push_back('i');
        dfs(ipush+1,ipop);
        build.pop();
        operate.pop_back();
    }
    if(ipop+1 <= ipush && ipop+1 <= length && build.top() == target[ipop]){
        char temp = build.top();
        build.pop();
        operate.push_back('o');
        dfs(ipush,ipop+1);
        build.push(temp);
        operate.pop_back();
    }
}
int main(){
    while(cin>>origion>>target){
        length = origion.size();
        cout<<"["<<endl;
        dfs(0,0);
        cout<<"]"<<endl;
    }
    return 0 ;
}