找规律 SGU 126 Boxes

 

题目地址：http://acm.sgu.ru/problem.php?contest=0&problem=126

 1 /*

 2  找规律，智商不够，看了题解  3  详细解释：http://blog.csdn.net/ahfywff/article/details/7432524

 4 */

 5 #include <cstdio>

 6 #include <cmath>

 7 #include <cstring>

 8 #include <string>

 9 #include <iostream>

10 #include <algorithm>

11 #include <queue>

12 #include <vector>

13 using namespace std; 14 

15 const int MAXN = 1e5 + 10; 16 const int INF = 0x3f3f3f3f; 17 

18 int GCD(int a, int b) 19 { 20     return b ? GCD (b, a % b) : a; 21 } 22 

23 int main(void)        //SGU 126 Boxes

24 { 25     //freopen ("C.in", "r", stdin);

26 

27     int n, m; 28 

29     while (~scanf ("%d%d", &n, &m)) 30  { 31         int ans; 32         if (n == 0 || m == 0) 33  { 34             ans = 0; 35  } 36         else

37  { 38             if (n < m) swap (n, m); 39             int k = GCD (n, m); 40             int x = n / k;  int y = m / k; 41             if ((x+y) & 1) 42  { 43                 ans = -1; 44  } 45             else

46  { 47                 int tmp = x + y; 48                 ans = 0; 49                 while (tmp > 1) 50  { 51                     if (tmp % 2 == 0) 52  { 53                         tmp /= 2; 54                         ans++; 55  } 56                     else

57  { 58                         ans = -1;    break; 59  } 60  } 61  } 62  } 63 

64         printf ("%d\n", ans); 65  } 66 

67     return 0; 68 }