青蛙的约会

扩展欧几里得

简单的经典题目

 

 1 #include <iostream>

 2 #include <cstdio>

 3 #include <cstring>

 4 #include <cmath>

 5 #include <algorithm>

 6 #define Mod 1000000007

 7 #define SMod 10007

 8 #define lll __int64

 9 #define ll long long

10 using namespace std;

11 #define N 1000007

12 

13 ll exgcd(ll a,ll b,ll &x,ll &y)

14 {

15     if(!b)

16     {

17         x = (ll)1,y = (ll)0;

18         return a;

19     }

20     ll r = exgcd(b,a%b,x,y);

21     ll t = x;

22     x = y;

23     y = t - a/b*y;

24     return r;

25 }

26 

27 ll gcd(ll a,ll b)

28 {

29     if(!b)

30         return a;

31     return gcd(b,a%b);

32 }

33 

34 int main()

35 {

36     ll x,y,m,n,L;

37     ll kx,ky;

38     while(scanf("%lld%lld%lld%lld%lld",&x,&y,&m,&n,&L)!=EOF)

39     {

40         ll nm = n-m;

41         ll delta = x-y;

42         if(nm < 0)

43         {

44             nm = m-n;

45             delta = y-x;

46         }

47         ll d = exgcd(nm,L,kx,ky);

48         if(delta%d)

49         {

50             puts("Impossible");

51             continue;

52         }

53         ll t = L/d;

54         //printf("%lld\n",t);

55         printf("%lld\n",res);

56     }

57     return 0;

58 }

代码君