POJ 1635 Subway tree systems-优快云博客

本文介绍了一种通过构建树结构并使用深度优先搜索（DFS）来重组和比较两个01串的方法。该方法首先根据输入串构建树，再通过DFS获取排序后的01串，最后比较两个串是否相同。

/*主要是根据输入串建树，然后对树DFS，重新获得一个排序后的01串。
对两个输入串分别运用上述方法分别得到两个排序后的01串，如果两个串相等则same,否则different
关键在于DFS时对子树返回的01串进行存储和排序，然后重组
比如对于
0100101100100111和0011000111010101，重组后分别变成：
0001101100101101和0001110011010101，不相等所以输出different
*/
#include <iostream>
#include <algorithm>
#include <string>
#include <vector>
#define MAX_N 3000
using namespace std;

struct tree
{
   tree *parent;
   tree *next; //第一个儿子
   tree *bro; //兄弟
   tree()
   {
       parent = next = bro = NULL;
   }
};
//建树
tree *buildTree(string str)
{
   int p;
   char ch;
   tree *root = new tree();
   tree *cur = root;
   for(p = 0; p < str.length(); p++)
   {
       ch = str[p];
       if(ch == '0')
       {
           tree *temp = new tree();
           temp->parent = cur;
           tree *nptr = cur;
           if(nptr->next)
           {
               nptr = nptr->next;
               while(nptr->bro)
                   nptr = nptr->bro;
               nptr->bro = temp;
           }
           else
               nptr->next = temp;
           cur = temp;
       }
       else if(ch == '1')
       {
           cur = cur->parent;
       }
   }
   return root;
}
tree *beginRoot;
//重组DFS，获得排序后的01串
string travelSeq(tree *root)
{
   tree *nptr = root;
   vector<string> vec;
   //遍历所有儿子
   if(nptr->next)
   {
       vec.push_back(travelSeq(nptr->next));
       nptr = nptr->next;
       while(nptr->bro)
       {
           vec.push_back(travelSeq(nptr->bro));
           nptr = nptr->bro;
       }
   }
   //排序
   sort(vec.begin(), vec.end());
   vector<string>::iterator iter = vec.begin();
   string res = "";
   //组合
   for(; iter != vec.end(); iter++)
       res += *iter;
   if(root != beginRoot) res = '0' + res + '1';
   return res;
}
int main()
{
   int caseN;
   string str1, str2;
   scanf("%d", &caseN);
   while(caseN--)
   {
       cin>>str1>>str2;
       beginRoot = buildTree(str1);
       str1 = travelSeq(beginRoot);
       beginRoot = buildTree(str2);
       str2 = travelSeq(beginRoot);
       if(str1 == str2)
           printf("same/n");
       else
           printf("different/n");
   }
   return 0;
}