1.2 namenum 遞歸枚舉

Name That Number

Among the large Wisconsin cattle ranchers, it is customary to brand cows with serial numbers to please the Accounting Department. The cow hands don't appreciate the advantage of this filing system, though, and wish to call the members of their herd by a pleasing name rather than saying, "C'mon, #4734, get along."

Help the poor cowhands out by writing a program that will translate the brand serial number of a cow into possible names uniquely associated with that serial number. Since the cow hands all have cellular saddle phones these days, use the standard Touch-Tone(R) telephone keypad mapping to get from numbers to letters (except for "Q" and "Z"):

          2: A,B,C     5: J,K,L    8: T,U,V
          3: D,E,F     6: M,N,O    9: W,X,Y
          4: G,H,I     7: P,R,S

Acceptable names for cattle are provided to you in a file named "dict.txt", which contains a list of fewer than 5,000 acceptable cattle names (all letters capitalized). Take a cow's brand number and report which of all the possible words to which that number maps are in the given dictionary which is supplied as dict.txt in the grading environment (and is sorted into ascending order).

For instance, the brand number 4734 produces all the following names:

GPDG GPDH GPDI GPEG GPEH GPEI GPFG GPFH GPFI GRDG GRDH GRDI
GREG GREH GREI GRFG GRFH GRFI GSDG GSDH GSDI GSEG GSEH GSEI
GSFG GSFH GSFI HPDG HPDH HPDI HPEG HPEH HPEI HPFG HPFH HPFI
HRDG HRDH HRDI HREG HREH HREI HRFG HRFH HRFI HSDG HSDH HSDI
HSEG HSEH HSEI HSFG HSFH HSFI IPDG IPDH IPDI IPEG IPEH IPEI
IPFG IPFH IPFI IRDG IRDH IRDI IREG IREH IREI IRFG IRFH IRFI
ISDG ISDH ISDI ISEG ISEH ISEI ISFG ISFH ISFI

As it happens, the only one of these 81 names that is in the list of valid names is "GREG".

Write a program that is given the brand number of a cow and prints all the valid names that can be generated from that brand number or ``NONE'' if there are no valid names. Serial numbers can be as many as a dozen digits long.
PROGRAM NAME: namenum
INPUT FORMAT
A single line with a number from 1 through 12 digits in length.
SAMPLE INPUT (file namenum.in)

4734

OUTPUT FORMAT
A list of valid names that can be generated from the input, one per line, in ascending alphabetical order.
SAMPLE OUTPUT (file namenum.out)

GREG
/* ID: xdzhbin1 LANG: C++ TASK:namenum */ #include <string> #include <fstream> #include <vector> #include <algorithm> #include <iterator> #include <iostream> using namespace std; //鍵位對應的字符 char keypad[10][3] = { {0}, {0}, {'A','B','C'}, //2 {'D','E','F'}, //3 {'G','H','I'}, {'J','K','L'}, {'M','N','O'}, {'P','R','S'}, {'T','U','V'}, {'W','X','Y'} //9 }; bool space = false; //標記是否已經找到 //遞歸枚舉 /* * 參數 ret 結果字符串 * cur 當前索引 * nclicks 摁了幾個數字鍵 * dict 字典序列 * out 輸出結果序列 */ void recur(string ret, int cur, int nclicks, vector<int>& vin, vector<string>& dict, ofstream& out) { if(cur == nclicks) //深度足夠，查看結果 { //cout<<ret<<" "; //在字典中，直接輸出 if(binary_search(dict.begin(),dict.end(),ret)) { out<<ret<<endl; space = true; } return ; } ret[cur] = keypad[vin[cur]][0]; //產生數字對應的第一個字符 recur(ret,cur+1,nclicks,vin,dict,out); //遞歸後面的字符 ret[cur] = keypad[vin[cur]][1]; //第二個 recur(ret,cur+1,nclicks,vin,dict,out); ret[cur] = keypad[vin[cur]][2]; recur(ret,cur+1,nclicks,vin,dict,out); cur++; } //打印全排列 int main() { ifstream indata("namenum.in",ios::in); ifstream indict("dict.txt",ios::in); //字典序列 ofstream out("namenum.out",ios::out); vector<int> vin(13); char ch; int i = 0; while(indata>>ch) vin[i++] = ch - '0';//依次讀入數字 istream_iterator<string> ii(indict); //流迭代器，用輸入文件流初始化 istream_iterator<string> eos; //默認構造，流結束標誌 vector<string> dict(ii,eos); //用兩個流迭代器初始化向量，整個流的內容都存到了向量中 string ret(" ",i); //爲遞歸結果申請空間 recur(ret,0,i,vin,dict,out);//開始遞歸 if(!space) out<<"NONE"<<endl; return 0; }