#include "bits/stdc++.h"
using namespace std;
#define int long long
const int MAXN = 3e5 + 10;
const int MOD = 1e9 + 7;
mt19937_64 rng((int)std::chrono::steady_clock::now().time_since_epoch().count());
int rnd(int x, int y) {
int u = uniform_int_distribution<int>(x, y)(rng); return u;
}
int bm(int b, int p) {
if(p==0) return 1 % MOD;
int r = bm(b, p >> 1);
if(p&1) return (((r*r) % MOD) * b) % MOD;
return (r*r) % MOD;
}
int inv(int b) {
return bm(b, MOD-2);
}
int fastlog(int x) {
return (x == 0 ? -1 : 64 - __builtin_clzll(x) - 1);
}
void printcase(int i) { cout << "Case #" << i << ": "; }
int n, m, k;
pair<int, int> edges[69];
int dsu[69];
int set_of(int u) {
if(dsu[u] == u) return u;
return dsu[u] = set_of(dsu[u]);
}
void union_(int u, int v) {
dsu[set_of(u)] = set_of(v);
}
vector<pair<int,int> >adj[69];
int bruh[69][69];
bool dfs(int node, int prv, int tar, int id) {
if(tar == node) return 1;
for(pair<int,int>x:adj[node]){
if(x.first==prv) continue;
bool d=dfs(x.first,node,tar,id);
if(d) {
bruh[id][x.second]=1;
return 1;
}
}
return 0;
}
void solve(int tc) {
cin >> n >> m >> k;
for(int i=1; i<n; i++) {
int u, v;
cin >> u >> v;
edges[i] = {u, v};
adj[u].push_back({v, i});
adj[v].push_back({u, i});
}
for(int i=1; i<=m; i++) {
int a, b;
cin >> a >> b;
dfs(a, -1, b, i-1);
}
int ans = 0;
for(int i=0; i<(1<<m); i++) {
for(int j=1; j<n; j++) dsu[j] = j;
for(int j=0; j<m; j++) {
if(!(i & (1<<j))) continue;
vector<int> v;
for(int k=1; k<n; k++) if(bruh[j][k]) v.push_back(k);
for(int k=1; k<v.size(); k++) union_(v[k-1], v[k]);
}
set<int>st;
for(int j=1;j<n;j++)st.insert(set_of(j));
int bruh = bm(k, st.size());
if(__builtin_popcountll(i) & 1) ans = (ans+MOD-bruh) % MOD;
else ans = (ans+bruh) % MOD;
}
cout << ans << '\n';
}
int32_t main() {
ios::sync_with_stdio(0); cin.tie(0);
int t = 1; //cin >> t;
for(int i=1; i<=t; i++) solve(i);
}
// 勿忘初衷
Compilation message
Main.cpp: In function 'void solve(long long int)':
Main.cpp:68:21: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
68 | for(int k=1; k<v.size(); k++) union_(v[k-1], v[k]);
| ~^~~~~~~~~
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
212 KB |
Output is correct |
2 |
Correct |
1 ms |
340 KB |
Output is correct |
3 |
Correct |
1 ms |
212 KB |
Output is correct |
4 |
Correct |
0 ms |
340 KB |
Output is correct |
5 |
Correct |
1 ms |
340 KB |
Output is correct |
6 |
Correct |
0 ms |
340 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
0 ms |
332 KB |
Output is correct |
2 |
Correct |
1 ms |
340 KB |
Output is correct |
3 |
Correct |
1 ms |
212 KB |
Output is correct |
4 |
Correct |
1 ms |
336 KB |
Output is correct |
5 |
Correct |
0 ms |
212 KB |
Output is correct |
6 |
Correct |
1 ms |
340 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
332 KB |
Output is correct |
2 |
Correct |
1 ms |
336 KB |
Output is correct |
3 |
Correct |
1 ms |
340 KB |
Output is correct |
4 |
Correct |
1 ms |
340 KB |
Output is correct |
5 |
Correct |
9 ms |
336 KB |
Output is correct |
6 |
Correct |
0 ms |
212 KB |
Output is correct |
7 |
Correct |
0 ms |
336 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
336 KB |
Output is correct |
2 |
Correct |
1 ms |
340 KB |
Output is correct |
3 |
Correct |
0 ms |
212 KB |
Output is correct |
4 |
Correct |
1 ms |
340 KB |
Output is correct |
5 |
Correct |
7 ms |
212 KB |
Output is correct |
6 |
Correct |
8 ms |
212 KB |
Output is correct |
7 |
Correct |
1 ms |
340 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
212 KB |
Output is correct |
2 |
Correct |
1 ms |
340 KB |
Output is correct |
3 |
Correct |
1 ms |
212 KB |
Output is correct |
4 |
Correct |
0 ms |
340 KB |
Output is correct |
5 |
Correct |
1 ms |
340 KB |
Output is correct |
6 |
Correct |
0 ms |
340 KB |
Output is correct |
7 |
Correct |
0 ms |
332 KB |
Output is correct |
8 |
Correct |
1 ms |
340 KB |
Output is correct |
9 |
Correct |
1 ms |
212 KB |
Output is correct |
10 |
Correct |
1 ms |
336 KB |
Output is correct |
11 |
Correct |
0 ms |
212 KB |
Output is correct |
12 |
Correct |
1 ms |
340 KB |
Output is correct |
13 |
Correct |
1 ms |
332 KB |
Output is correct |
14 |
Correct |
1 ms |
336 KB |
Output is correct |
15 |
Correct |
1 ms |
340 KB |
Output is correct |
16 |
Correct |
1 ms |
340 KB |
Output is correct |
17 |
Correct |
9 ms |
336 KB |
Output is correct |
18 |
Correct |
0 ms |
212 KB |
Output is correct |
19 |
Correct |
0 ms |
336 KB |
Output is correct |
20 |
Correct |
1 ms |
336 KB |
Output is correct |
21 |
Correct |
1 ms |
340 KB |
Output is correct |
22 |
Correct |
0 ms |
212 KB |
Output is correct |
23 |
Correct |
1 ms |
340 KB |
Output is correct |
24 |
Correct |
7 ms |
212 KB |
Output is correct |
25 |
Correct |
8 ms |
212 KB |
Output is correct |
26 |
Correct |
1 ms |
340 KB |
Output is correct |
27 |
Correct |
46 ms |
340 KB |
Output is correct |
28 |
Correct |
1 ms |
340 KB |
Output is correct |
29 |
Correct |
1 ms |
340 KB |
Output is correct |
30 |
Correct |
46 ms |
340 KB |
Output is correct |
31 |
Correct |
11 ms |
340 KB |
Output is correct |
32 |
Correct |
7 ms |
468 KB |
Output is correct |
33 |
Correct |
1 ms |
340 KB |
Output is correct |
34 |
Correct |
6 ms |
340 KB |
Output is correct |
35 |
Correct |
24 ms |
340 KB |
Output is correct |
36 |
Correct |
58 ms |
340 KB |
Output is correct |
37 |
Correct |
27 ms |
340 KB |
Output is correct |