1023 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 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 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
解题
大数相加,用string代替;
#include<iostream>
#include<algorithm>
#include<cstring>
#include<vector>
using namespace std;
int main()
{
vector<int> book(10,0);
string t;
cin>>t;
for(char i:t){
book[i-'0']++;
}
reverse(t.begin(),t.end());
bool flag=0;
string r="";
int temp;
for(int i=0;i<t.size();i++)
{
temp=2*(t[i]-'0');
if(flag) temp+=1;
if(temp>=10){
r+=(temp%10+'0');
flag=1;
}
else {
r+=(temp+'0');
flag=0;
}
book[temp%10]--;
}
if(flag) {
r+='1';
book[1]--;
}
reverse(r.begin(),r.end());
bool q=1;
for(int i=0;i<10;i++)
if(book[i]!=0)
{
cout<<"No"<<endl;
q=0;
break;
}
if(q)
cout<<"Yes"<<endl;
cout<<r;
}
注意点
1.reverse函数可以让string反向,操作进位更方便;
2.需要判断最后是否进位+1;
3.若更高的进位,需要carry记录每一位进位的数量,两数相加进位最高为1,用flag即可;