PAT(甲级)1031 Hello World for U （20 分)

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

简析：计算好n1和n2就好，其他就是正常输出。

#include<iostream>
#include<string>
using namespace std;
int main()
{
    string str;
    cin >> str;
    int N = str.length();
    int n1 = (N + 2) / 3;
    int n2 = (N + 2) - 2 * n1;
    for (int i = 0; i < n1 - 1;i++)
    {
        cout << str[i];
        for (int j = 0; j < n2 - 2;j++)
            cout << ' ';
        cout << str[N - 1 - i]<<'\n';
    }
    string str1 = str.substr(n1 - 1, n2);
    cout << str1;
    return 0;
}