1031. Hello World for U (20)

PAT

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：一串字符串，按U型输出，其中n1行，n2列，n3==n1;
条件：n1<=n2&&n1+n2+n3-2==字符串长n，求取最大n1

代码

#include<cstdio>#include<cstring>int main()  {      char a[100];      while(scanf("%s",a)!=EOF){        int n = strlen(a);          int n1 = 0, n2 = 0;          for(int i = 0; i < n; i++){//求出n1的最大值              n1 = i;              n2 = n+2-2*n1;              if(n2 < n1) break;          }          n1--;          n2 = n+2-2*n1;          for(int i = 0; i < n1-1; i++){            printf("%c",a[i]);            for(int j = 0;j< n2-2;j++)                printf(" ");            printf("%c\n",a[n-1-i]);        }        for(int i = n1-1; i < n1-1+n2; i++)            printf("%c",a[i]);        printf("\n");    }}