HDU - 6624 fraction

题目

题解

#include 
using namespace std;
typedef long long ll;
 
void gao(ll pa,ll pb,ll qa,ll qb,ll &x,ll &y){
    ll z=(pa+pb-1)/pb;
    if(z<=qa/qb){
        x=z; y=1; return;
    }
    pa-=(z-1)*pb; qa-=(z-1)*qb;
    gao(qb,qa,pb,pa,y,x);
    x+=(z-1)*y;
}
 
ll a,p,x,y;
 
int main(){
    int T; cin>>T;
    while(T--){
        scanf("%lld%lld",&p,&a);
        gao(p,a,p,a-1,x,y);
        ll z=x*a-p*y;
        printf("%lld/%lld\n",z,x);
    }
    return 0;
}