UVa 400 Unix ls 命令

UVA 400

The computer company you work for is introducing a brand new computer line and is developing a

new Unix-like operating system to be introduced along with the new computer. Your assignment is to

write the formatter for the ls function.

Your program will eventually read input from a pipe (although for now your program will read

from the input file). Input to your program will consist of a list of (F) filenames that you will sort

(ascending based on the ASCII character values) and format into (C) columns based on the length (L)

of the longest filename. Filenames will be between 1 and 60 (inclusive) characters in length and will be

formatted into left-justified columns. The rightmost column will be the width of the longest filename

and all other columns will be the width of the longest filename plus 2. There will be as many columns

as will fit in 60 characters. Your program should use as few rows (R) as possible with rows being filled

to capacity from left to right.

Input

The input file will contain an indefinite number of lists of filenames. Each list will begin with a line

containing a single integer (1 ≤ N ≤ 100). There will then be N lines each containing one left-justified

filename and the entire line’s contents (between 1 and 60 characters) are considered to be part of the

filename. Allowable characters are alphanumeric (a to z, A to Z, and 0 to 9) and from the following set

{._-} (not including the curly braces). There will be no illegal characters in any of the filenames and

no line will be completely empty.

Immediately following the last filename will be the N for the next set or the end of file. You should

read and format all sets in the input file.

Output

For each set of filenames you should print a line of exactly 60 dashes (-) followed by the formatted

columns of filenames. The sorted filenames 1 to R will be listed down column 1; filenames R + 1 to 2R

listed down column 2; etc.

Sample Input

10

tiny

2short4me

very_long_file_name

shorter

size-1

size2

size3

much_longer_name

12345678.123

mid_size_name

12

Weaser

Alfalfa

Stimey

Buckwheat

Porky

Joe

Darla

Cotton

Butch

Froggy

Mrs_Crabapple

P.D.

19

Mr._French

Jody

Buffy

Sissy

Keith

Danny

Lori

Chris

Shirley

Marsha

Jan

Cindy

Carol

Mike

Greg

Peter

Bobby

Alice

Ruben

Sample Output

题目很长，题意大致是 先输入一个正整数n，后面是n个文件名，排序后按列优先的方式左对齐输出。假设最长的文件名有M个字符，则最右列有M字符，其他列都是M+2字符。

#include<iostream>
#include<algorithm>
#include<cstring>
#include<cstdio>
using namespace std;
const int maxcol=60;

4000
const int maxn=105;
string filenames[maxn];
void print(const string &s,int len,char extra)
{
cout<<s;
for(int i=0;i<len-s.length();i++)
{
cout<<extra;
}
}
int main()
{
int n;
while(cin>>n)
{
int m=0;
for(int i=0;i<n;i++)
{
cin>>filenames[i];
m=max(m,(int)filenames[i].length());
}
int cols=(maxcol-m)/(m+2)+1,rows=(n-1)/cols+1;
print("",60,'-');
cout<<"\n";
sort(filenames,filenames+n);
for(int r=0;r<rows;r++)
{
for(int c=0;c<cols;c++)
{
int idx=c*rows+r;
if(idx<n)
print(filenames[idx],c==cols-1?m:m+2,' ');
}
cout<<endl;
}
}
return 0;
}