题目：http://pat.zju.edu.cn/contests/pat-a-practise/1031
分析：
简单题，调整数组的输出次序就可以了。
输入数组长度为len。n1 = n3 = (len+2)/3; n2 = len - n1 - n3;
第一行最左边对应的是原数组的第一个字符，最后边对应的是原数组的最后一个字符。总共输出n1行。
题目描述：
Given any string of N (>=5) characters, you are asked to form the characters into the shape of U. For example, "helloworld" can be printed as:
h d
e l
l r
lowo
That is, the characters must be printed in the original order, starting top-down from the left vertical line with n 1 characters, then left to right along the bottom line with n 2 characters, and finally bottom-up along the vertical line with n 3 characters. And more, we would like U to be as squared as possible -- that is, it must be satisfied that n 1 = n 3 = max { k| k <= n 2 for all 3 <= n 2 <= N } with n 1 + n 2 + n 3 - 2 = N.
Input Specification:
Each input file contains one test case. Each case contains one string with no less than 5 and no more than 80 characters in a line. The string contains no white space.
Output Specification:
For each test case, print the input string in the shape of U as specified in the description.
Sample Input:
helloworld!
Sample Output:
h !
e d
l l
lowor
参考代码：
#include<iostream>
#include<string.h>
using namespace std;
#define max 85
char input[max]; int main()
{
int len;
int n1,n2,n3;
int i,j;
cin>>input;
len = strlen(input);
n1 = n3 = (len + 2) / 3 ;
n2 = len - 2*n1;
for(i=0; i<n1-1; i++)
{
cout<<input[i];
for(j=0; j<n2; j++) cout<<" ";
cout<<input[len-1-i]<<endl;
}
for(j=i; j<len-i; j++)
cout<<input[j];
cout<<endl; return 0;
}