A palindromic number reads the same both ways. The largest palindrome made from the product of two 2-digit numbers is 9009 = 91  99.

Find the largest palindrome made from the product of two 3-digit numbers.

#include<stdio.h>
#include<math.h>
#include<string.h>
#include<ctype.h>
#include<stdlib.h>
#include<stdbool.h> bool palindromic(int n) //判断一个整数是否为回文数
{
char s[];
sprintf(s,"%d",n); //将整数n保存在字符数组s中
int i,len;
len=strlen(s);
for(i=; i<len/; i++)
{
if(s[i]!=s[len-i-])
return false;
}
return true;
} bool have_the_factor(int n) //判断是否含有两个3位数的因数
{
int s=;
int r,b;
while(s>)
{
if((n%s)== && ((n/s)> && (n/s)<))
return true;
s--;
}
return false;
} int main()
{
int i=;
while(i>)
{
if(palindromic(i) && have_the_factor(i))
{
printf("%d\n",i);
break;
}
i--;
}
return ;
}
Answer:
906609

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