Online Judge►UVa

[UVa] 100 - The 3n + 1 problem

重新再寫過一次這題，時間從0.955進步到0.075，差別在於做過的記錄下來，有想到區間似乎也可以記錄下來？但用二維記憶體就爆炸了。

而那些0.000的是怎麼一回事..

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
#include <iostream>
#include <vector>
using namespace std;
int main()
{
	vector <int> v ;
	v.resize(1000000) ;
	for ( int i = 0 ; i < 1000000 ; i ++ )
		v[i] = 0 ;
	for ( int n , m ; cin >> n >> m ; )
	{
		cout << n << " " << m  ;
		if ( n > m )
		{
			int temp = n ;
			n = m ;
			m = temp ;
		}
		int maxlength = 0 ;
		for ( int i = n ; i <= m ; i ++ )
		{
			if ( v[i] != 0 )
				maxlength = max(maxlength,v[i]);
			else
			{
				int j = i , count = 0 ;
				while ( j > 1 )
				{
					if ( j % 2 == 0 )
						j /= 2 ;
					else
						j = 3 * j + 1 ;
					count ++ ;
				}
				v[i] = count ;
				maxlength = max(maxlength,v[i]);
			}
		}
		cout << " " << maxlength + 1 << endl ;
	}
	return 0;
}