USACO Palindromic Squares

March 17, 2010

“We generate all the squares from 1 to 300 and check to see which are palindromes. “ 慢慢算就是了～不过不太熟悉C的函数、过程什么的，没用到。

/*
ID: djgreen
LANG: C
PROB: palsquare
*/

#include <stdio.h>
#include <stdbool.h>

const char s[20]={'0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F','G','H','I','J'};
int main()
{
    FILE *in=fopen("palsquare.in","r"),*out=fopen("palsquare.out","w");
    int base,n,new[17],old[17],p,p2,i,temp;
    long num;
    bool find;

    fscanf(in,"%d",&base;);
    fclose(in);
    for (n=1;n<=300;n++)
    {
        num=n*n;

        //convert(num)
        p=0;
        while (true)
        {
            new[p]=num%base;
            num=num/base;
            if (num==0) break;
            p++;
        }

        //palindromic?
        p2=0;
        find=true;
        for (i=0;i<=p;i++)
        {
            if (new[i]!=new[p-i])
            {
                find=false;
                break;
            }
        }
        if (find)
        {
            temp=n;
            while (true)
            {
                old[p2]=temp%base;
                temp=temp/base;
                if (temp==0) break;
                p2++;
            }
            for (i=p2;i>=0;i--) fprintf(out,"%c",s[old[i]]);
            fprintf(out," ");
            for (i=0;i<=p;i++) fprintf(out,"%c",s[new[i]]);
            fprintf(out,"\n");
        }
    }
    fclose(out);
}

```