PAT_自测4_Have Fun with Numbers

题目： https://pta.patest.cn/pta/test/17/exam/4/question/263
自测-4 Have Fun with Numbers   (20分)

Notice that the number 123456789 is a 9-digit number consisting exactly the numbers from 1 to 9, with no duplication. Double it we will obtain 246913578, which happens to be another 9-digit number consisting exactly the numbers from 1 to 9, only in a different
permutation. Check to see the result if we double it again!

Now you are suppose to check if there are more numbers with this property. That is, double a given number with kk digits,
you are to tell if the resulting number consists of only a permutation of the digits in the original number.

Input Specification:

Each input contains one test case. Each case contains one positive integer with no more than 20 digits.

Output Specification:

For each test case, first print in a line "Yes" if doubling the input number gives a number that consists of only a permutation of the digits in the original number, or "No" if not. Then in the next line, print the doubled number.

Sample Input:

1234567899

Sample Output:

Yes
2469135798

题意&解题；  case是 不超过20位，所以自带数据类型不足，需要写一个用数组表示的大数加乘函数。

/**
* https://pta.patest.cn/pta/test/17/exam/4/question/263 * 数据结构练习 00-自测4. Have Fun with Numbers (20)
*/

#include <iostream>
#include <string>
#include <stdlib.h>
#include <stdio.h>

using namespace std;

string multipleNum(string str, int n);
bool compareStr(string str1, string str2);

int main(int argc, char const *argv[])
{

string str, result;
cin >> str;
// str = "012345678990";

result = multipleNum(str, 2);

bool isSame = compareStr(str, result);
if(isSame){
cout<<"Yes\n"<<result<<endl;
}else{
cout<<"No\n"<<result<<endl;
}
return 0;
}

string multipleNum(string str, int n) //n<10
{
int addIn = 0; //进位
int length = str.size();
string strReturn = "";
for(int pos = length-1; pos>=0; pos--){
int num = (int)(str[pos] - '0'); //str[pos]是char格式，用ASCII记录

int result = num * n + addIn;
addIn = result/10;
result = result%10;

strReturn.insert((string::size_type)0,1,result+'0');
}
if(0!=addIn){
strReturn.insert((string::size_type)0,1,addIn+'0');
}
return strReturn;
}

bool compareStr(string str1, string str2){
if(str1.size() != str2.size())
return false;

int length = str1.size();
int count1[10] = {0};
int count2[10] = {0};

for( int i = 0 ; i < length ; i++ )
{ //对str计算，最大length为str.size()
count1[str1[i]-'0']++;
count2[str2[i]-'0']++;
}
for( int i = 0 ; i < 10 ; i++ )
{ //对array比较，最大length为10 - [0,9]
// cout<<count1[i]<<" i="<<i<<" "<<count2[i]<<endl;
// if((count1[i] - count2[i]) <0)
if( count1[i] != count2[i] )
return false;
}
return true;
}