今天下午把最近一段时间CF做过的题整理下

先说着今天做的两个侮辱智商的题==

Description

A continued fraction of height n is a fraction of form . You are given two rational numbers, one is represented as  and the other one is represented as a finite fraction of height n. Check if they are equal.

Input

The first line contains two space-separated integers p, q(1 ≤ q ≤ p ≤ 1018) — the numerator and the denominator of the first fraction.

The second line contains integer n(1 ≤ n ≤ 90) — the height of the second fraction. The third line contains n space-separated integersa1, a2, ..., an(1 ≤ ai ≤ 1018) — the continued fraction.

Please, do not use the %lld specifier to read or write 64-bit integers in С++. It is preferred to use the cin, cout streams or the %I64dspecifier.

Output

Print "YES" if these fractions are equal and "NO" otherwise.

Sample Input

Input 
9 4
2
2 4
Output 
YES
Input 
9 4
3
2 3 1
Output 
YES
Input 
9 4
3
1 2 4
Output 
NO

Hint

In the first sample .

In the second sample .

In the third sample .

一开始觉得既然是B题，小case啊，浮点数挨个除吧，然而浮点数相除一定会出现问题！本题正误而的解法是把每次读入的a移到等式左边，如果读入的a大于左边的式子或者没结束就出现了有一项等于0，那么一定输出no 
#include <iostream>
using namespace std;
long long n,p,q,a;
int main()
{
    //freopen("cin.txt","r",stdin);

        cin>>p>>q>>n;
        while(n)
        {
            cin>>a;
            if(q==0||a>(p/q)) break;
            long long t=q;
            q=p-a*q;
            p=t;
            n--;
        }
        if(n||q) cout<<"NO"<<endl;
        else cout<<"YES"<<endl;

    return 0;
}

这几天选择语言的时候都默认是php ，今天居然变成html了，这是提示我该学那些了吗……