PAT-A 真题- 1031. Hello World for U

原题干：

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 n₁ characters, then left to right along the bottom line with n₂ characters, and finally bottom-up along the vertical line with n₃ characters. And more, we would like U to be as squared as possible -- that is, it must be satisfied that n₁ = n₃ = max { k| k <= n₂ for all 3 <= n₂ <= N } with n₁ + n₂ + n₃ - 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

题目大意： 给定一个字符串，要求将这个字符串按照U形输出

但是要保证左侧的字符数小于等于底部的字符数，找到满足这个条件的最大侧边字符数。

这种输出图案的题目，画几个找找规律就好了。

把10～～13个字符的字符串都画一遍，就会发现侧边字符数量等于（总长度+2） / 3

这样就可以知道底部字符数量是总数量+2-2*侧边数量

接着循环输出就好啦。

代码很简单，不做过详细的解释。：

#include <iostream>
#include <string>
using namespace std;

int main(){
    string input;
    cin >> input;
    int len = input.length();
    int side = (len + 2) / 3;
    int buttom = len + 2 - (2 * side);
    for(int i = 0; i < side - 1; i++){
        cout << input[i];
        for(int j = 0; j < buttom - 2; j++) cout << ' ';
        cout << input[len - 1 - i];
        cout << endl;
    }
    for(int i = side - 1; i < side + buttom - 1; i++)
        cout << input[i];
    cout << endl;
    return 0;
}