cf Perfect Pair

http://codeforces.com/contest/318/problem/C

 1 #include <cstdio>
 2 #include <cstring>
 3 #include <algorithm>
 4 using namespace std;
 5 long long j;
 6 long long x,y,m;
 7 int main()
 8 {
 9     scanf("%I64d%I64d%I64d",&x,&y,&m);
10     if(x>=m||y>=m)
11     {
12         printf("0\n");
13         return 0;
14     }
15     else if(x<=0&&y<=0)
16     {
17         printf("-1\n");
18         return 0;
19     }
20     if(x<0)
21     {
22         j=(-x)/y+1;
23         x+=j*y;
24     }
25     if(y<0)
26     {
27         j=(-y)/x+1;
28         y+=j*x;
29     }
30     while(1)
31     {
32         if(!(x<m&&y<m)) break;
33         if(x>y) y=x+y;
34         else x=x+y;
35         j++;
36     }
37     printf("%I64d\n",j);
38     return 0;
39 }
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posted @ 2014-04-15 21:48  null1019  阅读(119)  评论(0)  编辑  收藏  举报