HNU Joke with permutation （深搜dfs）

题目链接：http://acm.hnu.cn/online/?action=problem&type=show&id=13341&courseid=0

Joke with permutationTime Limit: 3000ms, Special Time Limit:7500ms, Memory Limit:65536KBTotal submit users: 85, Accepted users: 57Problem 13341 : Special judgeProblem description

Joey had saved a permutation of integers from 1 to n in a text file. All the numbers were written as decimal numbers without leading spaces.

Then Joe made a practical joke on her: he removed all the spaces in the file.

Help Joey to restore the original permutation after the Joe’s joke!

Input

The input file contains a single line with a single string — the Joey’s permutation without spaces.

The Joey’s permutation had at least 1 and at most 50 numbers.

Output

Write a line to the output file with the restored permutation. Don’t forget the spaces!

If there are several possible original permutations, write any one of them.

Sample Input

4111109876532

Sample Output

4 1 11 10 9 8 7 6 5 3 2

Problem SourceNEERC 2014

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题目大意：将一串完整的字符串分成1~n个数。将空格补进去，并将其输出。

解题思路：1、注意这个n是可以求出来的

　　　　　2、一个数字一个数字比较，只要满足这个数字小于n，还有保证这个数字没有访问过就ok啦

　　　

详见代码。

 1 #include <iostream> 2 #include <cstdio> 3 #include <cstring> 4  5 using namespace std; 6  7 int n,flag; 8 char ch[110]; 9 int ans[110];10 bool vis[110];11 12 bool dfs(int i,int k)13 {14     if (flag==1)15         return true;16     if (k==n+1)17     {18         for (int i=1;i<k-1;i++)19         {20             printf ("%d ",ans[i]);21         }22         printf ("%d\n",ans[k-1]);23         flag=1;24         return true;25     }26     if (ch[i]-'0'<=n&&!vis[ch[i]-'0']&&ch[i]-'0'>0)27     {28         ans[k]=ch[i]-'0';29         vis[ch[i]-'0']=1;30         if(dfs(i+1,k+1)) return true;31         vis[ch[i]-'0']=0;32     }33     if ((ch[i]-'0')*10+ch[i+1]-'0'<=n&&(ch[i]-'0')*10+ch[i+1]-'0'>9&&!vis[(ch[i]-'0')*10+ch[i+1]-'0'])34     {35         ans[k]=(ch[i]-'0')*10+ch[i+1]-'0';36         vis[(ch[i]-'0')*10+ch[i+1]-'0']=1;37         if(dfs(i+2,k+1)) return true;38         vis[(ch[i]-'0')*10+ch[i+1]-'0']=0;39     }40     return false;41 }42 43 int main()44 {45     while (scanf("%s",ch)!=EOF)46     {47         flag=0;48         memset(ans,0,sizeof(ans));49         memset(vis,0,sizeof(vis));50         int len=strlen(ch);51         if (len>9)52             n=(len-9)/2+9;53         else54             n=len;55         dfs(0,1);//dfs();56     }57     return 0;58 }