#include <bits/stdc++.h>
using i64 = long long;
constexpr i64 mod = 1000000007;
i64 add(i64 a, i64 b) {
return (a + b) % mod;
}
i64 sub(i64 a, i64 b) {
return (a + mod - b) % mod;
}
i64 mul(i64 a, i64 b) {
return (a * b) % mod;
}
void eadd(i64 &a, i64 b) {
a = add(a, b);
}
void esub(i64 &a, i64 b) {
a = sub(a, b);
}
void emul(i64 &a, i64 b) {
a = mul(a, b);
}
i64 pow(i64 a, i64 n) {
i64 ret = 1;
while (n != 0) {
if (n % 2 == 1) {
emul(ret, a);
}
emul(a, a);
n /= 2;
}
return ret;
}
int main() {
int N;
i64 D;
std::cin >> N >> D;
if (N == 2) {
std::cout << pow(2, D) << std::endl;
return 0;
}
std::vector<int> A(N - 1), B(N - 1);
std::vector<std::vector<int>> tree(N - 1);
for (int i = 0; i < N - 1; ++i) {
std::cin >> A[i] >> B[i];
--A[i], --B[i];
tree[A[i]].push_back(B[i]);
tree[B[i]].push_back(A[i]);
}
// first game
// rerooting
std::vector<bool> dpParent(N);
auto dfs1 = [&](auto &&self, const int v, const int p) -> void {
for (int i = 0; i < (int)tree[v].size(); ++i) {
const int t = tree[v][i];
if (t == p) {
std::swap(tree[v][i], tree[v][0]);
} else {
self(self, t, v);
}
}
};
dfs1(dfs1, 0, -1);
auto dfs2 = [&](auto &&self, const int v, const int p) -> bool {
if (v != 0 and tree[v].size() == 1) {
return dpParent[v] = false;
}
bool ret = false;
for (int i = 0; i < (int)tree[v].size(); ++i) {
const int t = tree[v][i];
if (t == p) {
continue;
}
ret |= not self(self, t, v);
}
return dpParent[v] = ret;
};
dfs2(dfs2, 0, -1);
std::vector<std::vector<bool>> dpChildren;
auto dfs3 = [&](auto &&self, const int v, const int p, bool dpvPar) -> bool {
};
}
Compilation message
startrek.cpp: In lambda function:
startrek.cpp:86:5: warning: no return statement in function returning non-void [-Wreturn-type]
86 | };
| ^
startrek.cpp: In function 'int main()':
startrek.cpp:84:10: warning: variable 'dfs3' set but not used [-Wunused-but-set-variable]
84 | auto dfs3 = [&](auto &&self, const int v, const int p, bool dpvPar) -> bool {
| ^~~~
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Runtime error |
1 ms |
340 KB |
Execution killed with signal 11 |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Incorrect |
0 ms |
212 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Runtime error |
1 ms |
340 KB |
Execution killed with signal 11 |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Runtime error |
1 ms |
340 KB |
Execution killed with signal 11 |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Runtime error |
1 ms |
340 KB |
Execution killed with signal 11 |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Runtime error |
1 ms |
340 KB |
Execution killed with signal 11 |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Runtime error |
1 ms |
340 KB |
Execution killed with signal 11 |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Runtime error |
1 ms |
340 KB |
Execution killed with signal 11 |
2 |
Halted |
0 ms |
0 KB |
- |