浙大 PAT Advanced level 1023. Have Fun with Numbers (20)

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 k 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 file 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

输入的数字最大可以有20位，因此需要用string类型来记录输入，并要自己完成乘法运算。

需要考虑double后的结果是否和输入位数相同，以及结果和输入的数字组成是否相同。

// 全部accept#include <iostream>using namespace std;#define MAXLENGTH 23int input[MAXLENGTH];int output[MAXLENGTH];int judge[10];int main(){  char buffer[MAXLENGTH];  int length = 0;  int carry = 0;                // 乘法进位  bool flag = true;    cin.getline(buffer, MAXLENGTH);    while ('\0' != buffer[length])  {    ++length;  }  for (int i = MAXLENGTH-1, j = length-1; j != -1; --i, --j)  {    input[i] = buffer[j] - '0';  }  for (int i = MAXLENGTH-1; i != -1; --i)  {    output[i] = (input[i]*2+carry)%10;    carry = (input[i]*2+carry)/10;  }    for (int i = MAXLENGTH-1; i != MAXLENGTH-length-1; --i)  {    ++judge[input[i]];    --judge[output[i]];  }  for (int i = 0; i != 10; ++i)  {    if (0 != judge[i])    {      flag = false;      break;    }  }  if (flag)  {    cout << "Yes" << endl;  }  else  {    cout << "No" << endl;  }    flag = false;  for (int i = 0; i != MAXLENGTH; ++i)  {    if (0 != output[i])    {      flag = true;    }    if (flag)    {      cout << output[i];    }  }  cout << endl;  system("pause");  return 0;}// 有一个case不过#if 0#include <iostream>using namespace std;#define MAXLENGTH 23int input[MAXLENGTH];int output[MAXLENGTH];int judge[10];int main(){char buffer[MAXLENGTH];int length = 0;int carry = 0;// 乘法进位bool flag = true;cin.getline(buffer, MAXLENGTH);while ('\0' != buffer[length]){++length;}for (int i = MAXLENGTH-1, j = length-1; j != -1; --i, --j){input[i] = buffer[j] - '0';}for (int i = MAXLENGTH-1; i != -1; --i){output[i] = (input[i]*2+carry)%10;carry = (input[i]*2+carry)/10;}for (int i = MAXLENGTH-1; i != -1; --i){++judge[input[i]];--judge[output[i]];}for (int i = 1; i != 10; ++i){if (0 != judge[i]){flag = false;break;}}if (flag){cout << "Yes" << endl;}else{cout << "No" << endl;}flag = false;for (int i = 0; i != MAXLENGTH; ++i){if (0 != output[i]){flag = true;}if (flag){cout << output[i];}}cout << endl;system("pause");return 0;}#endif