USACO_Section 1.2_palsquare
#include
<
stdio.h
>
#include < string .h >
void conv( char numb[], int n, int base )
{
int num[ 18 ],len = 0 ,j;
while (n / base )
{
num[len] = n % base ;
++ len;
n /= base ;
}
num[len] = n;
for (j = len;j >= 0 ; -- j)
{
if (num[j] > 9 )numb[len - j] = num[j] + 55 ;
else numb[len - j] = num[j] + ' 0 ' ;
}
numb[len + 1 ] = ' \0 ' ;
return ;
}
int main()
{
FILE * fin, * fout;
fin = fopen( " palsquare.in " , " r " );
fout = fopen( " palsquare.out " , " w " );
int base ,i,len = 0 ,j;
fscanf(fin, " %d " , & base );
for (i = 1 ;i <= 300 ; ++ i)
{
char square[ 18 ] = { ' \0 ' },num[ 10 ] = { ' \0 ' };
int flag = 1 ;
conv(num,i, base );
conv(square,i * i, base );
len = strlen(square);
for (j = 0 ;j <= len / 2 ; ++ j)
{
if (square[j] != square[len - j - 1 ])
{
flag = 0 ;
break ;
}
}
if (flag)fprintf(fout, " %s %s\n " ,num,square);
}
return 0 ;
}
#include < string .h >
void conv( char numb[], int n, int base )
{
int num[ 18 ],len = 0 ,j;
while (n / base )
{
num[len] = n % base ;
++ len;
n /= base ;
}
num[len] = n;
for (j = len;j >= 0 ; -- j)
{
if (num[j] > 9 )numb[len - j] = num[j] + 55 ;
else numb[len - j] = num[j] + ' 0 ' ;
}
numb[len + 1 ] = ' \0 ' ;
return ;
}
int main()
{
FILE * fin, * fout;
fin = fopen( " palsquare.in " , " r " );
fout = fopen( " palsquare.out " , " w " );
int base ,i,len = 0 ,j;
fscanf(fin, " %d " , & base );
for (i = 1 ;i <= 300 ; ++ i)
{
char square[ 18 ] = { ' \0 ' },num[ 10 ] = { ' \0 ' };
int flag = 1 ;
conv(num,i, base );
conv(square,i * i, base );
len = strlen(square);
for (j = 0 ;j <= len / 2 ; ++ j)
{
if (square[j] != square[len - j - 1 ])
{
flag = 0 ;
break ;
}
}
if (flag)fprintf(fout, " %s %s\n " ,num,square);
}
return 0 ;
}
我还是习惯用C写……所以把代码贴上来的时候发现stdio是黑色的，而“base”是蓝色的。
就这样吧。
题目：
Palindromic Squares
Rob Kolstad
Rob Kolstad
Palindromes are numbers that read the same forwards as backwards. The number 12321 is a typical palindrome.
Given a number base B (2 <= B <= 20 base 10), print all the integers N (1 <= N <= 300 base 10) such that the square of N is palindromic when expressed in base B; also print the value of that palindromic square. Use the letters 'A', 'B', and so on to represent the digits 10, 11, and so on.
Print both the number and its square in base B.
PROGRAM NAME: palsquare
INPUT FORMAT
A single line with B, the base (specified in base 10).SAMPLE INPUT (file palsquare.in)
10
OUTPUT FORMAT
Lines with two integers represented in base B. The first integer is the number whose square is palindromic; the second integer is the square itself.SAMPLE OUTPUT (file palsquare.out)
1 1 2 4 3 9 11 121 22 484 26 676 101 10201 111 12321 121 14641 202 40804 212 44944 264 69696
没有什么复杂的算法，因为这一节讲的就是“
the brute force, straight-forward, try-them-all method of finding the answer.
”