algorithm_2024/src/P2822/P2822.cpp

#include <iostream>
#include <algorithm>
#include <map>

using ull = unsigned long long;
#define NV(v)#v<<" : "<<(v)

static ull t, k, n, m, ans;
static std::map<ull,ull> fact_map;
static std::map<std::pair<ull,ull>,ull> C_map;

static ull fact(const ull n)noexcept{
    if(n==0)return 1;
    const auto it = fact_map.find(n);
    if(it !=  fact_map.end())return (*it).second;
    ull ret {1};
    for(ull i{2};i<=n;i++){
        ret*=i;
    }
    fact_map.insert({n,ret});
    return ret;
}

static ull C(const ull n, const ull m)noexcept{
    const auto it = C_map.find({n,m});
    if(it!=C_map.end())return (*it).second;
    const ull ret = (fact(n))/(fact(m)*fact(n-m));
    C_map.insert({{n,m},ret});
    return ret;
}

int main(){
    // std::cout<<NV(fact(0))<<'\n'<<NV(fact(3))<<'\n';
    std::iostream::sync_with_stdio(false), std::cin.tie(nullptr), std::cout.tie(nullptr);
    std::cin>>t>>k;

    for(ull i {0};i<t;i++){
        std::cin>>n>>m;
        ans = 0;
        for(ull i {0};i<=n;i++){
            for(ull j{0};j<=std::min(i,m);j++){
                if(C(i,j)%k==0)ans++;
            }
        }
        std::cout<<ans<<'\n';
    }
}