九度 1464：Hello World for U

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 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.

思路

1. N1+N2+N3-2= N, 尽量追求 N1,N2,N3 平均, 所以要么取 N3 = ceil((N+2)/3), 要么取 N1=N2=(N+2)/3-1. 第一种取法有不适合的情况

代码

#include <iostream>
#include <stdio.h>
#include <string>
#include <math.h>
using namespace std;

int n1, n2, n3;

int main() {
    string input;
    while(cin >> input) {
        int len = input.size();
        n1 = n2 = (len+2)/3 -1;
        n3 = len - 2*n1;

        for(int i = 0; i < n1; i ++) {
            cout << input[i];
            for(int j = 0; j < n3-2; j ++) {
                cout << ' ';
            }
            cout << input[len-i-1];
            cout << endl;
        }

        for(int i = 0; i < n3; i ++) {
            cout << input[i+n1];
        }
        cout << endl;
    }
    return 0;
}