USACO Section 1.2.5 Palindromic Squares

题目

<center style="font&#45;size&#58;14px&#59;"> Palindromic Squares
Rob Kolstad </center>

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

思路

其实这个题目很简单,可是为毛我做了好久呢?其实,主要是我一贯试用cpp的string,这会想练练纯c,突然发现这玩意好繁琐。。又加上边聊边写,于是乎一道水题搞了一个多小时。

学习:
malloc(sizeof(char)*100); // 不清零
calloc(100,sizeof(char)); // 清零
然后,没了。

代码

#include <cstdio>
#include <cstring>
#include <cstdlib>
const int dr[22]={'0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F','G','H','I','J','K'};
const int N=300;
int n;
char * mir(char *a){
	int l=strlen(a);
	char *b=(char*)calloc(22,sizeof(char));
	for (int i(0);i<l;i++) b[i]=a[l-i-1];
	b[l]='\0';
	return b;
}
char * base(int k,int n){
	char *s=(char*)calloc(22,sizeof(char));
	while (k){
		int l=strlen(s);
		s[l]=dr[k%n];
		s[l+1]='\0';
		k/=n;
	}
	return mir(s);
}
int main(){
	freopen("palsquare.in","r",stdin);
	freopen("palsquare.out","w",stdout);
	scanf("%d",&n);
	for (int i(1);i<=N;i++){
		char *b1=base(i,n);
		char *b2=base(i*i,n);
		if (!strcmp(b2,mir(b2))){
		   printf("%s %s\n",b1,b2);
		}
	}
	return 0;
}


全部评论

相关推荐

不愿透露姓名的神秘牛友
昨天 14:10
点赞 评论 收藏
分享
人力小鱼姐:实习经历没有什么含金量,咖啡店员迎宾这种就别写了,其他两段包装一下 想找人力相关的话,总结一下个人优势,结合校园经历里有相关性的部分,加一段自我评价
点赞 评论 收藏
分享
05-20 13:59
门头沟学院 Java
米黑子米黑子:你这个成绩不争取下保研?
点赞 评论 收藏
分享
评论
点赞
收藏
分享

创作者周榜

更多
牛客网
牛客网在线编程
牛客网题解
牛客企业服务