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

題目大意：一串字串，按U型輸出，其中n1行，n2列，n3==n1;
條件：n1<=n2&&n1+n2+n3-2==字串長n，求取最大n1

程式碼

#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");
    }
}