[哈希&&模拟]Happy Number uva10591

 

Problem C	Happy Number
Time Limit	1 Second

 

Let the sum of the square of the digits of a positive integer S0 be represented by S1. In a similar way, let the sum of the squares of the digits ofS1 be represented
by S2 and so on. If Si = 1 for some i ³ 1, then the original integer S0 is said to be Happy number. A number, which is not happy, is called Unhappy number.
For example 7 is a Happy number since 7 -> 49 -> 97 -> 130 -> 10 -> 1 and 4 is an Unhappy number since 4 -> 16 -> 37 -> 58 -> 89 -> 145 -> 42 -> 20 -> 4.

 

Input

The input consists of several test cases, the number of which you are given in the first line of the input. Each test case consists of one line containing a single positive integer N smaller than 109.

 

Output

For each test case, you must print one of the following messages:

 

Case #p: N is a Happy number.

Case #p: N is an Unhappy number.

 

Here p stands for the case number (starting from 1). You should print the first message if the number N is a happy number. Otherwise, print the second line.

 

Sample Input	Output for Sample Input
3 7 4 13	Case #1: 7 is a Happy number. Case #2: 4 is an Unhappy number. Case #3: 13 is a Happy number.

 

Problemsetter: Mohammed Shamsul Alam

International Islamic University Chittagong

Special thanks to Muhammad Abul Hasan

一道直接可以模拟的哈希的水题，注意happy number的最大值不超过9*81。开的哈希数组1000就够用。

#include<iostream>
#include<cstring>

using namespace std;

int tag[1000];

int Happy(int num)
{
int sum=0;
while(num!=0)
{
sum=sum+(num%10)*(num%10);
num=num/10;
}
return sum;
}

int main()
{
int n,m;
cin>>n;
for(int i=1;i<=n;i++)
{
cin>>m;
memset(tag,0,sizeof(tag));
int flag=0;
int s=Happy(m);
while(tag[s]==0)
{
if(s==1)
{
flag=1;
break;
}
tag[s]=1;
s=Happy(s);
}
cout<<"Case #"<<i<<": "<<m<<" is";
if(flag==1) cout<<" a Happy number."<<endl;
else cout<<" an Unhappy number."<<endl;
}
return 0;
}