【c++】PAT (Advanced Level)1019. General Palindromic Number (20)

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本文介绍了一个算法，用于判断一个十进制整数在特定进制下是否为回文数，并提供了一个C++实现示例。

1019. General Palindromic Number (20)

时间限制

400 ms

内存限制

32000 kB

代码长度限制

16000 B

判题程序

Standard

作者

CHEN, Yue

A number that will be the same when it is written forwards or backwards is known as a Palindromic Number. For example, 1234321 is a palindromic number. All single digit numbers are palindromic numbers.

Although palindromic numbers are most often considered in the decimal system, the concept of palindromicity can be applied to the natural numbers in any numeral system. Consider a number N > 0 in base b >= 2, where it is written in standard notation with k+1 digits a_i as the sum of (a_ibⁱ) for i from 0 to k. Here, as usual, 0 <= a_i < b for all i and a_k is non-zero. Then N is palindromic if and only if a_i = a_k-i for all i. Zero is written 0 in any base and is also palindromic by definition.

Given any non-negative decimal integer N and a base b, you are supposed to tell if N is a palindromic number in base b.

Input Specification:

Each input file contains one test case. Each case consists of two non-negative numbers N and b, where 0 <= N <= 10⁹ is the decimal number and 2 <= b <= 10⁹ is the base. The numbers are separated by a space.

Output Specification:

For each test case, first print in one line "Yes" if N is a palindromic number in base b, or "No" if not. Then in the next line, print N as the number in base b in the form "a_k a_k-1 ... a₀". Notice that there must be no extra space at the end of output.

Sample Input 1:

27 2

Sample Output 1:

Yes
1 1 0 1 1

Sample Input 2:

121 5

Sample Output 2:

No
4 4 1

啊啊啊1.第5个测试点是0

1.以前用字符串做，其实无所谓来把数组开大一点就好了。。。

#include <iostream>
#include <string>
using namespace std;

int main(){
	int a,b,c[10000];
	while(cin>>a>>b){
		int loc=0;

		if(a==0){
			cout<<"Yes"<<endl<<"0";
			return 0;
		}
		while(a>0){
			c[loc++]=a%b;
			a=a/b;
		}
		bool ff=true;
		int i;
		for( i=0;i<loc/2;i++){
			if(c[i]!=c[loc-1-i]){
				ff=false;
				break;
			}
		}
		if(ff){
			cout<<"Yes"<<endl;
		}else{
			cout<<"No"<<endl;
		}
		ff=true;
		for(i=loc-1;i>=0;i--){
			if(ff){
				ff=false;
			}else{
				cout<<" ";
			}
			cout<<c[i];
		}
	}	
	return 0;
}