UVA 400 Unix ls

 1 #include<iostream>
 2 #include<algorithm>
 3 #include<string>
 4 using namespace std;
 5 const int maxcol = 60;
 6 const int maxn = 100 + 5;
 7 string filename[maxn];
 8 //输出字符串s，长度不足len时，补字符extra
 9 void print(const string&s,int len,char extra)
10 {
11     cout << s;
12     for (int i = s.length(); i < len; i++)//或者i=0;i<len-s.length()
13     {
14         cout << extra;
15     }
16 }
17 int main()
18 {
19     int n;
20     while (cin >> n)
21     {
22         int M=0;//M是最长的长度
23         for (int i = 0; i < n; i++)
24         {
25             cin >> filename[i];
26             M = max(M,(int)filename[i].length());
27         }
28         //计算列数cols和行数rows
29         int cols = (maxcol + 2) / (M + 2);
30         int rows = (n - 1) / cols + 1;//技巧
31         sort(filename,filename + n);
32         print("",60,‘-‘);
33         cout << "n";
34         for (int r = 0; r < rows; r++)//最外层是行
35         {
36             for (int c = 0; c < cols; c++)//列
37             {
38                 //输出
39                 int idx = c*rows + r;
40                 /*
41                 举例：
42                 0  3  6  9  ->c
43                 1  4  7
44                 2  5  6
45                 ↓
46                 r
47                 可推算出
48                 */
49                 if(idx<n)
50                 print(filename[idx],c == cols-1 ? M : M + 2,‘ ‘);//三目运算符
51             }
52             cout << "n";
53         }
54     }
55     return 0;
56 }