(Problem 4)Largest palindrome product

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[10];
	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=0; i<len/2; i++)
	{
		if(s[i]!=s[len-i-1])
			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=999;
	int r,b;
	while(s>100)
	{
		if((n%s)==0 && ((n/s)>100  && (n/s)<1000))
			return true;
		s--;
	}
	return false;
}

int main()
{
	int i=1000000;
	while(i>0)
	{
		if(palindromic(i) && have_the_factor(i))
		{
			printf("%d\n",i);
			break;
		}
		i--;
	}
	return 0;
}

Answer:
906609

posted @ 2013-07-24 11:38  cpoint  阅读(206)  评论(0编辑  收藏  举报
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