Submission #764854

#	Time	Username	Problem	Language	Result	Execution time	Memory
764854		dxz05	Šarenlist (COCI22_sarenlist)	C++17	10 / 110	1 ms	468 KiB

Main

#pragma GCC optimize("Ofast,O3,unroll-loops")
#pragma GCC target("avx2")

#include <bits/stdc++.h>

using namespace std;

#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define bpc(x) __builtin_popcount(x)
#define bpcll(x) __builtin_popcountll(x)
#define MP make_pair
#define BIT(x, i) (((x) >> (i)) & 1)
//#define endl '\n'

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

typedef long long ll;
const int MOD = 1e9 + 7;
const int N = 61;

long long binpow(long long n, long long k, long long mod = MOD){ // n^k % mod
    long long res = 1;
    while (k > 0){
        if (k & 1) res = res * n % mod;
        n = n * n % mod;
        k >>= 1;
    }
    return res;
}

vector<int> operator+ (vector<int> vx, const vector<int>& vy){
    for (int y : vy) vx.push_back(y);
    return vx;
}

int d[N][N];
vector<int> p[N][N];

void solve(){
    int n, m, k;
    cin >> n >> m >> k;

    for (int i = 1; i <= n; i++){
        fill(d[i] + 1, d[i] + n + 1, 1e9);
        d[i][i] = 0;
    }

    for (int i = 1; i < n; i++){
        int u, v;
        cin >> u >> v;
        d[u][v] = d[v][u] = 1;
        p[u][v] = p[v][u] = {i};
    }

    for (int t = 1; t <= n; t++){
        for (int i = 1; i <= n; i++){
            for (int j = 1; j <= n; j++){
                if (d[i][j] > d[i][t] + d[t][j]){
                    d[i][j] = d[i][t] + d[t][j];
                    p[i][j] = p[i][t] + p[t][j];
                }
            }
        }
    }

    vector<pair<int, int>> pairs(m);
    for (int i = 0; i < m; i++){
        int x, y;
        cin >> x >> y;
        if (x > y) swap(x, y);
        pairs[i] = MP(x, y);
        assert(x != y);
    }

    sort(all(pairs));
    pairs.erase(unique(all(pairs)), pairs.end());

    m = (int) pairs.size();

    ll ans = binpow(k, n - 1);
    for (int mask = 1; mask < (1 << m); mask++){
        set<int> s;
        for (int i = 0; i < m; i++){
            if (!BIT(mask, i)) continue;
            for (int j : p[pairs[i].first][pairs[i].second]){
                s.insert(j);
            }
        }

        ll cur = k * binpow(k, n - 1 - (int) s.size()) % MOD;
        if (bpc(mask) & 1){
            ans += MOD - cur;
        } else {
            ans += cur;
        }

        if (ans >= MOD) ans -= MOD;
    }

    cout << ans << endl;

}

int main(){
    clock_t startTime = clock();
    ios_base::sync_with_stdio(false);

#ifdef LOCAL
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
#endif

    int test_cases = 1;
//    cin >> test_cases;

    for (int test = 1; test <= test_cases; test++){
        // cout << (solve() ? "YES" : "NO") << endl;
        solve();
    }

#ifdef LOCAL
    cerr << "Time: " << int((double) (clock() - startTime) / CLOCKS_PER_SEC * 1000) << " ms" << endl;
#endif

    return 0;
}

Compilation message (stderr)

Main.cpp: In function 'int main()':
Main.cpp:106:13: warning: unused variable 'startTime' [-Wunused-variable]
  106 |     clock_t startTime = clock();
      |             ^~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 0 / 15
• Subtask 3: 0 / 10
• Subtask 4: 0 / 10
• Subtask 5: 0 / 65