Romantic

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others) Total Submission(s): 5638    Accepted Submission(s): 2391 Problem Description The Sky is Sprite. The Birds is Fly in the Sky. The Wind is Wonderful. Blew Throw the Trees Trees are Shaking, Leaves are Falling. Lovers Walk passing, and so are You.  ................................Write in English class by yifenfei   Girls are clever and bright. In HDU every girl like math. Every girl like to solve math problem! Now tell you two nonnegative integer a and b. Find the nonnegative integer X and integer Y to satisfy X*a + Y*b = 1. If no such answer print "sorry" instead.   Input The input contains multiple test cases. Each case two nonnegative integer a,b (0<a, b<=2^31)   Output output nonnegative integer X and integer Y, if there are more answers than the X smaller one will be choosed. If no answer put "sorry" instead.    Sample Input 77 51 10 44 34 79   Sample Output 2 -3 sorry 7 -3   Author yifenfei   Source HDU女生专场公开赛——谁说女子不如男   Recommend lcy

裸的exgcd。

#include <iostream> using namespace std; typedef long long int ll; ll exgcd(ll a,ll b,ll &x,ll &y) { ll ans,temp; if(b==0) { x=1; y=0; return a; } ans=exgcd(b,a%b,x,y); temp=x; x=y; y=temp-a/b*y; return ans; } ll cal(ll a,ll b,ll c) { ll x,y; ll gcd=exgcd(a,b,x,y); if(c%gcd!=0) return -1; x*=c/gcd; b/=gcd; if(b<0) b=-b; ll ans=x%b; if(ans<=0) ans+=b; return ans; } int main() { ll a,b; while(cin>>a>>b) { ll ans=cal(a,b,1); if(ans==-1) cout<<"sorry"<<endl; else cout<<ans<<" "<<(1-ans*a)/b<<endl; } return 0; }