Submission #3024808


Source Code Expand

#include <bits/stdc++.h>
#define FOR(i, begin, end) for(int i=(begin);i<(end);i++)
#define REP(i, n) FOR(i,0,n)
#define SORT(a) sort(a.begin(), a.end())
#define int long long
using namespace std;

typedef pair<int, int> Pii;

template<typename T>
void readvec(vector<T> &a);
void readindex(vector<int> &a);

int extgcd(int a, int b, int &x, int &y){
    int d = a;
    if(b != 0){
        d = extgcd(b, a % b, y, x);
        y -= (a / b) * x;
    }else{
        x = 1;
        y = 0;
    }
    return d;
}

int mod_inverse(int a, int m){
    int x, y;
    extgcd(a, m, x, y);
    return (m + x % m) % m;
}


signed main(){

    int M = 998244353;
    int N, A, B, K, x, y;
    cin >> N >> A >> B >> K;

    int g = extgcd(A, B, x, y);
    if(K % g != 0){
        cout << 0;
        return 0;
    }

    x *= K / g;
    y *= K / g;
    //これでAx+By=K

    int a = A / g;
    int b = B / g;
    //X=x+kb,Y=y-ka

    int k_min = -1 * (x / b);
    int k_max = y / a;

    vector<int> fact(N + 1, 1);
    FOR(i, 1, N + 1){
        fact[i] = (fact[i - 1] * i) % M;
    }

    int ans = 0;
    FOR(k, k_min, k_max + 1){
        int X = x + k * b;
        int Y = y - k * a;
        if(X < 0 || Y < 0 || X > N || Y > N) continue;
        int tmp1 = (((fact[N] * mod_inverse(fact[X], M)) % M) * mod_inverse(fact[N - X], M)) % M;
        int tmp2 = (((fact[N] * mod_inverse(fact[Y], M)) % M) * mod_inverse(fact[N - Y], M)) % M;
        ans = (ans + tmp1 * tmp2) % M;
    }

    cout << ans;

    return 0;
}


template<typename T>
void readvec(vector<T> &a){
    REP(i, a.size()){
        cin >> a[i];
    }
}
void readindex(vector<int> &a){
    REP(i, a.size()){
        cin >> a[i];
        a[i]--;
    }
}

Submission Info

Submission Time
Task B - RGB Coloring
User sumitacchan
Language C++14 (GCC 5.4.1)
Score 700
Code Size 1789 Byte
Status AC
Exec Time 332 ms
Memory 2560 KB

Judge Result

Set Name Sample All
Score / Max Score 0 / 0 700 / 700
Status
AC × 3
AC × 27
Set Name Test Cases
Sample sample01.txt, sample02.txt, sample03.txt
All sample01.txt, sample02.txt, sample03.txt, in01.txt, in02.txt, in03.txt, in04.txt, in05.txt, in06.txt, in07.txt, in08.txt, in09.txt, in10.txt, in11.txt, in12.txt, in13.txt, in14.txt, in15.txt, in16.txt, in17.txt, in18.txt, in19.txt, in20.txt, in21.txt, sample01.txt, sample02.txt, sample03.txt
Case Name Status Exec Time Memory
in01.txt AC 4 ms 2560 KB
in02.txt AC 4 ms 2560 KB
in03.txt AC 4 ms 2560 KB
in04.txt AC 4 ms 2560 KB
in05.txt AC 4 ms 2560 KB
in06.txt AC 4 ms 2560 KB
in07.txt AC 4 ms 2560 KB
in08.txt AC 2 ms 896 KB
in09.txt AC 4 ms 2560 KB
in10.txt AC 3 ms 2048 KB
in11.txt AC 4 ms 2176 KB
in12.txt AC 2 ms 1024 KB
in13.txt AC 55 ms 1664 KB
in14.txt AC 12 ms 640 KB
in15.txt AC 11 ms 1024 KB
in16.txt AC 7 ms 512 KB
in17.txt AC 61 ms 1792 KB
in18.txt AC 130 ms 2560 KB
in19.txt AC 332 ms 2560 KB
in20.txt AC 300 ms 2560 KB
in21.txt AC 1 ms 256 KB
sample01.txt AC 1 ms 256 KB
sample02.txt AC 1 ms 256 KB
sample03.txt AC 2 ms 896 KB