Submission #696677

#	Time	Username	Problem	Language	Result	Execution time	Memory
696677		socpite	Šarenlist (COCI22_sarenlist)	C++17	110 / 110	37 ms	332 KiB

Main

#include<bits/stdc++.h>
using namespace std;

#define f first
#define s second

typedef long long ll;
typedef long double ld;

const int mod = 1e9+7;
const int maxn = 65;
const ll inf = 1e18+5;

int n, m, k;

int _s, _t;

vector<int> edg[maxn];
vector<int> alle[maxn];

int vis[65];
ll pw[65];
vector<int> tr[maxn];

vector<pair<int, int>> g[maxn];

bool dfs(int x, int p, int id){
    //cout << _s << " " << x << "\n";
    if(x == _t)return 1;
    for(auto v: g[x]){
        if(v.f == p)continue;
        if(dfs(v.f, x, id)){
            //cout << v.s << "\n";
            alle[id].push_back(v.s);
            return 1;
        }
    }
    return 0;
}

void _fill(int x){
    vis[x] = 1;
    for(auto v: tr[x])if(!vis[v])_fill(v);
}

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    cin >> n >> m >> k;
    //cout << (1LL*k*k - k)%mod << "\n";
    pw[0] = 1;
    for(int i = 1; i <= n; i++)pw[i] = pw[i-1]*k%mod;
    for(int i = 1; i < n; i++){
        int a, b;
        cin >> a >> b;
        g[a].push_back({b, i});
        g[b].push_back({a, i});
    }
    for(int i = 0; i < m; i++){
        cin >> _s >> _t;
        dfs(_s, 0, i);
    }
    ll ans = 0;
    for(int i = 0; i < (1<<m); i++){
        for(int j = 1; j < n; j++){
            vis[j] = 0;
            tr[j].clear();
        }
        for(int j = 0; j < m; j++){
            if(i&(1<<j)){
                for(int k = 1; k < alle[j].size(); k++){
                    int a = alle[j][0], b = alle[j][k];
                    tr[a].push_back(b);
                    tr[b].push_back(a);
                }
            }
        }
        int cnt = 0;
        for(int j = 1; j < n; j++){
            if(!vis[j]){
                cnt++;
                _fill(j);
            }
        }
        if(__builtin_popcount(i)&1)ans -= pw[cnt];
        else ans += pw[cnt];
        ans%=mod;
    }
    if(ans < 0)ans += mod;
    cout << ans;
}

Compilation message (stderr)

Main.cpp: In function 'int main()':
Main.cpp:71:34: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   71 |                 for(int k = 1; k < alle[j].size(); k++){
      |                                ~~^~~~~~~~~~~~~~~~

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