Codeforces 585C Alice, Bob, Oranges and Apples（规律）

题目链接：Codeforces 585C Alice, Bob, Oranges and Apples

解题思路

次数其实就是gcd过程，最后一次要减1。

代码

#include <cstdio>
#include <cstring>
#include <vector>
#include <algorithm>

using namespace std;
typedef long long ll;

ll x, y;
vector<ll> ans;

ll gcd (ll a, ll b) {
    if (b == 0) return a;
    ans.push_back(a / b);
    return gcd(b, a % b);
}

int main () {
    ans.clear();
    scanf("%lld%lld", &x, &y);

    ll k = gcd(x, y);
    if (k != 1)
        printf("Impossible\n");
    else {
        int n = ans.size();
        ans[n-1]--;

        int v = x < y;
        for (int i = 0; i < n; i++) {
            if (ans[i] == 0) continue;
            printf("%lld%c", ans[i], 'A' + v);
            v ^= 1;
        }
        printf("\n");
    }
    return 0;
}