51nod 1185 威佐夫游戏 V2

思路：

威佐夫博弈 + 乘法模拟。

实现：

#include <iostream>
#include <cstdio>
using namespace std;
typedef long long ll;

const ll tmp[3] = { 618033988, 749894848, 204586834 };
const ll mod = 1e9;

int main()
{
    int t;
    ll a, b;
    cin >> t;
    while (t--)
    {
        cin >> a >> b;
        if (a < b)
            swap(a, b);
        ll x = a - b;
        ll c = a - b;
        ll p = c / mod, l = c % mod;
        ll a1 = l * tmp[2];
        ll a2 = p * tmp[2] + l * tmp[1] + a1 / mod;
        ll a3 = p * tmp[1] + l * tmp[0] + a2 / mod;
        ll a4 = c + p * tmp[0] + a3 / mod;
        cout << (a4 == b ? 'B' : 'A') << endl;
    }
    return 0;
}