Han Xin and His Troops【excrt】【python實現】

題目鏈接：https://ac.nowcoder.com/acm/contest/890/D
思路：這個題就是中國剩餘定理的模板題，只不過會爆$long \ long$，所以用$python$寫的非遞歸的$exgcd+excrt$版本。
AC代碼：

def ex_gcd(m,n):
    if n==0:
        x=1
        y=0
        return (m,x,y)
    else :
        a1=1
        b=1
        a=0
        b1=0
        c=m
        d=n
        q=c//d
        r=c%d
        while r > 0:
            c=d
            d=r
            t=a1
            a1=a
            a=t-a*q
            t=b1
            b1=b
            b=t-q*b
            q=c//d
            r=c%d
        x=a
        y=b
        return (d, x, y)
 
def excrt(r,m,n):
    mo=m[0]
    re=r[0]
    for i in range(1,n):
        (d,x,y)=ex_gcd(mo,m[i])
        if (r[i]-re)%d!=0:
            return (0,re)
        x=(r[i]-re)//d*x%(m[i]//d)
        re=re+x*mo
        mo=mo//d*m[i]
        re=re%mo
 
    re=(re+mo)%mo
    return (1,re)
 
r = []
m = []
n, up = map(int, input().split())
for i in range(0, n):
    t1,t2=map(int, input().split())
    m.append(t1)
    r.append(t2)
 
(tmp,ans)=excrt(r,m,n)
if tmp==0:
    print("he was definitely lying")
elif ans>up:
    print("he was probably lying")
else:
    print(ans)