Submission #765058

#	Time	Username	Problem	Language	Result	Execution time	Memory
765058		dxz05	Šarenlist (COCI22_sarenlist)	C++17	20 / 110	5 ms	596 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;
        pairs[i] = MP(x, y);
    }

    if (n <= 15){
        int ans = 0;

        for (int mask = 0; mask < (1 << (n - 1)); mask++){
            vector<int> color(n, 1);

            for (int i = 0; i < n - 1; i++){
                if (mask & (1 << i)){
                    color[i + 1] = 2;
                }
            }

            bool ok = true;
            for (auto [x, y] : pairs){
                int c1 = false, c2 = false;
                for (int j : p[x][y]){
                    if (color[j] == 1) c1 = true;
                    if (color[j] == 2) c2 = true;
                }
                if (!c1 || !c2) ok = false;
            }
            if (ok) ans++;
        }

        cout << ans << endl;
        return;
    }

    ll ans = 1;
    int e = n - 1;

    for (auto [x, y] : pairs){
        int sz = p[x][y].size();
        e -= sz;
        ll cur = binpow(k, sz) + MOD - k;
        ans = ans * cur % MOD;
    }

    ans *= binpow(k, e);
    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:120:13: warning: unused variable 'startTime' [-Wunused-variable]
  120 |     clock_t startTime = clock();
      |             ^~~~~~~~~

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