f445: 263 - Number Chains

解題心得

照著題目敘述做就好。

程式碼

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

int descending(int n)
{
	int arr[10] = { 0 }, ans = 0;
	while (n)
	{
		arr[n % 10]++;
		n /= 10;
	}
	for (int i = 9; i >= 0; i--)
	{
		while (arr[i] != 0)
		{
			ans = ans * 10 + i;
			arr[i]--;
		}
	}
	return ans;
}
int ascending(int n)
{
	int arr[10] = { 0 }, ans = 0;
	while (n)
	{
		arr[n % 10]++;
		n /= 10;
	}
	for (int i = 0; i < 10; i++)
	{
		while (arr[i] != 0)
		{
			ans = ans * 10 + i;
			arr[i]--;
		}
	}
	return ans;
}
int main()
{
	int n;
	while (cin >> n && n)
	{
		vector<int> v;
		cout << "Original number was " << n << endl;
		while (true)
		{
			int ascend = ascending(n), descend = descending(n), result = descend - ascend;
			cout << descend << " - " << ascend << " = " << result << endl;
			
			if (v.size() != 0 && find(v.begin(), v.end(), result) != v.end())
				break;
			v.push_back(result);
			n = result;
		}
		cout << "Chain length " << v.size() + 1 << endl << endl;
		
	}
	return 0;
}