Company Macrohard has released it’s new version of editor Nottoobad, which can understand a few voice commands. Unfortunately, there are only two voice commands that it can understand – “repeat the last word”, “delete the last symbol”. However, when one uses “repeat the last word” the editor inserts a blank that separates the words. But the company claims that it is possible to type much faster – simply by less number of presses. For example, such a phrase like “this thin thing” requires only 6 presses of the keyboard.
|
Action |
Number of presses |
Content of the document |
|
Press "this" |
4 |
This |
|
Say “repeat the last word” |
0 |
this this |
|
Say “delete the last symbol” |
0 |
this thi |
|
Press "n" |
1 |
this thin |
|
Say “repeat the last word” |
0 |
this thin thin |
|
Press "g" |
1 |
this thin thing |
In order to increase the popularity of it’s product the company decided to organize a contest where the winner will be a person who types a given number of words with minimum number of presses. Moreover, the first word must be typed first, and all the others can be typed in arbitrary order. So, if words “apple”, “plum” and “apricote” must be typed, the word “apple” must be typed first, and the words “plum” and “apricote” can be switched. And the most important for you – you are going to take part in the contest and you have a good friend in the company, who told you the word which will be used in the contest. You want be a winner J, so you have to write a program which finds the order of the words, where the number of presses will be minimum.
Input
The first line of the input contains the T (1≤T≤15) the number of test cases. Then T test cases follow. The first line of each test contains a number N (1≤N≤100) – the number of words that must be pressed. Next N lines contain words – sequences of small Latin letters, not longer than 100 symbols. Remember that the first word must be pressed first!
Output
The first line of the output contains number X - the minimum number of presses, which one has to do in order to type all the words using editor Nottoobad. Next N lines contain the words in that minimum order. If there are several solutions, you can output one of them.
|
Sample Input |
Sample Output |
|
3 3 this thin thing 4 popcorn apple apricote plum 2 hello hello |
6 this thin thing 21 popcorn plum apricote apple 5 hello hello |
Problem source: Russian National Team Olympiad 2000
Problem author: Andrew Stankevich
Problem translation: Dmytro Chernysh
Problem solution: Andrew Stankevich, Dmytro Chernysh
題意：一種編輯器只能通過聲音做到兩種操作-“repeat the last word”, “delete the last symbol”，其他的都必須自己手動輸入，問輸入一些單詞，最少需要手寫輸入多少次。
思路：這是比較典型得貪心法了，要使得手寫輸入最少，首先要尋找出最大的匹配前綴，因此把所有的單詞按照字典序排序，得到得序列是最優，因爲前綴有匹配得都會排到相鄰位置。
代碼：
#include<iostream>
#include<algorithm>
#include<string>
using namespace std;
string st[200];
bool cmp(string str1,string str2)
{
return str1<str2;
}
int suffix(string str1,string str2)
{
int len=min(str1.size(),str2.size());
int i;
for(i=0;i<len;i++)
{
if(str1[i]!=str2[i]) break;
}
return i;
}
int main()
{
int n,m;
cin>>n;
while(n--)
{
cin>>m;
int i,j,k;
string str;
for(i=0;i<m;i++)
{
cin>>st[i];
}
sort(st,st+m,cmp);
int len=st[0].size();
for(i=1;i<m;i++)
{
len=len+st[i].size()-suffix(st[i-1],st[i]);
}
cout<<len<<endl;
for(i=0;i<m;i++)
cout<<st[i]<<endl;
}
}