Submission #635441

#	Time	Username	Problem	Language	Result	Execution time	Memory
635441		MohammadAghil	Sumtree (INOI20_sumtree)	C++17	10 / 100	222 ms	26632 KiB

Main

#include <bits/stdc++.h>
//#pragma GCC optimize ("Ofast,unroll-loops")
//#pragma GCC target ("avx2")
using namespace std;

typedef long long ll;
typedef pair<int, int> pp;

#define rep(i,l,r) for(int i = (l); i < (r); i++)
#define per(i,r,l) for(int i = (r); i >= (l); i--)
#define all(x) begin(x), end(x)
#define sz(x) (int)x.size()
#define pb push_back
#define ff first
#define ss second

void dbg(){
    cerr << endl;
}
template<typename Head, typename... Tail> void dbg(Head h, Tail... t){
    cerr << " " << h << ",";
    dbg(t...);
}
#define er(...) cerr << __LINE__ << " <" << #__VA_ARGS__ << ">:", dbg(__VA_ARGS__)

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

void IOS(){
    cin.tie(0) -> sync_with_stdio(0);
//    #ifndef ONLINE_JUDGE
//        freopen("inp.txt", "r", stdin);
//        freopen("out.txt", "w", stdout);
//    #endif
}

const ll mod = 1e9 + 7, maxn = 5e5 + 5, maxm = 20, inf = ll(1e9) + 5;

ll pw(ll a, ll b){
    if(!b) return 1;
    ll k = pw(a, b>>1ll);
    return  k*k%mod*(b&1ll?a:1ll)%mod;
}

vector<int> adj[maxn];
ll fac[maxn], inv[maxn];

ll C(int n, int r){
    if(r < 0 || r > n) return 0;
    return fac[n]*inv[r]%mod*inv[n-r]%mod;
}

int main(){ IOS();
    fac[0] = inv[0] = 1;

    rep(i,1,maxn){
        fac[i] = fac[i-1]*i%mod;
        inv[i] = pw(fac[i], mod-2);
    }

    int n, r; cin >> n >> r;

    rep(i,1,n){
        int u, v; cin >> u >> v; u--, v--;
        adj[u].pb(v), adj[v].pb(u);
    }
    int q; cin >> q;
    cout << C(r + n - 1, n - 1) << '\n';
    return 0;
}

• Subtask 1: 10 / 10
• Subtask 2: 0 / 20
• Subtask 3: 0 / 20
• Subtask 4: 0 / 20
• Subtask 5: 0 / 30