POJ1061青蛙的约会（扩展欧几里得） 

 1 #include <cstdio>
 2 #include <cstring>
 3 #include <algorithm>
 4 #include <math.h>
 5 #include <iostream>
 6 #include <stack>
 7 #include <set>
 8 #include <queue>
 9 #define MAX(a,b) (a) > (b)? (a):(b)
10 #define MIN(a,b) (a) < (b)? (a):(b)
11 #define mem(a) memset(a,0,sizeof(a))
12 #define INF 1000000007
13 #define MAXN 20005
14 using namespace std;
15 
16 __int64 GCD(__int64 a,__int64 b)
17 {
18     return a%b==0?b:GCD(b,a%b);
19 }
20 
21 void gcd(__int64 a,__int64 b,__int64 &x,__int64 &y)
22 {
23     if(!b){x=1;y=0;}
24     else{gcd(b,a%b,y,x); y-=x*(a/b);}
25 }
26 
27 int main()
28 {
29     __int64 X,Y,M,N,L;
30     while(~scanf("%I64d %I64d %I64d %I64d %I64d",&X,&Y,&M,&N,&L))
31     {
32         __int64 a = (N-M), b = L, c = (X-Y);
33         __int64 g = GCD(a,b);
34         if(c%g){ printf("Impossible\n"); continue;}
35         __int64 x, y;
36         gcd(a, b, x, y);
37         x*=(c/g);
38         if(x>0)x%=(b/g);
39         else x=x%(b/g)+(b/g);
40         printf("%I64d\n",x);
41     }
42     return 0;
43 }

 

posted @ 2013-07-17 23:43  再见~雨泉  阅读(249)  评论(0)    收藏  举报