洛谷 P5170 【模板】类欧几里得算法（三类经典类欧式子模板）

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#include
#include
using namespace std;
const int maxn = 1e6 + 10;
typedef long long ll;
const long long mod = 998244353;
const long long inv2 = 499122177;
const long long inv6 = 166374059;
ll t,n,a,b,c;
struct node{
	ll f,g,h;
};
node solve(long long a, long long b, long long c, long long n) {
    node ans, tmp;
    if(a == 0)
    {
        ans.f = (b / c) * (n + 1) % mod;
        ans.g = (b / c) * n % mod * (n + 1) % mod * inv2 % mod;
        ans.h = (b / c) * (b / c) % mod * (n + 1) % mod;
    }
    else if(a >= c || b >= c)
    {
        tmp = solve(a % c, b % c, c, n);
        ans.f = (tmp.f + n * (n + 1) % mod * inv2 % mod * (a / c) % mod + (n + 1) * (b / c) % mod) % mod;
        ans.g = (tmp.g + (a / c) * n % mod * (n + 1) % mod * (2 * n + 1) % mod * inv6 % mod + (b / c) * n % mod * (n + 1) % mod * inv2 % mod) % mod;
        ans.h = (tmp.h + (a / c) * (a / c) % mod * n % mod * (n + 1) % mod * (2 * n + 1) % mod * inv6 % mod + 
				(n + 1) * (b / c) % mod * (b / c) % mod + 2 * (a / c) % mod * tmp.g % mod + 2 * (b / c) % mod * tmp.f % mod + 
				2 * (a / c) % mod * (b / c) % mod * n % mod * (n + 1) % mod * inv2 % mod) % mod;
    }
    else
    {
        long long m = (a * n + b) / c;
        tmp = solve(c, c - b - 1, a, m - 1);
        ans.f = (n * (m % mod) % mod - tmp.f) % mod;
        ans.g = (n * (n + 1) % mod * (m % mod) % mod - tmp.f - tmp.h) % mod * inv2 % mod;
        ans.h = (n * (m % mod) % mod * ((m + 1) % mod) % mod - 2 * tmp.g - 2 * tmp.f - ans.f) % mod;
    }
    return ans;
}
int main() {
	scanf("%lld",&t);
	while(t--) {
		scanf("%lld%lld%lld%lld",&n,&a,&b,&c);
		node ans = solve(a,b,c,n);
		printf("%lld %lld %lld\n",(ans.f + mod) % mod,(ans.h + mod) % mod,(ans.g + mod) % mod);
	}
	return 0;
}