#include <bits/stdc++.h>
using namespace std;
long long n, d;
int a, b;
bool dp[200005];
vector<int> adj[200005];
bool dfs(int x, bool turn, int par = -1) {
bool cstate;
if(turn) {
cstate = 0;
for(int e:adj[x]) {
if(e == par) continue;
cstate |= dfs(e, !turn, x);
}
} else {
cstate = 1;
for(int e:adj[x]) {
if(e == par) continue;
cstate &= dfs(e, !turn, x);
}
}
return cstate;
}
long long custompow(long long x, long long y) {
long long res = 1;
for(;y;y>>=1,x=x*x%mod) if(y&1) res = res*x%mod;
return res;
}
int main() {
cin >> n >> d;
if(n == 2) {
cout << custompow(2, 2*d);
return 0;
}
assert(n <= 100 && d == 1);
for(int i=1;i<n;i++) {
cin >> a >> b;
adj[a].push_back(b); adj[b].push_back(a);
adj[a+100].push_back(b+100); adj[b+100].push_back(a+100);
}
int ans = 0;
for(int i=1;i<=n;i++) {
for(int j=1;j<=n;j++) {
adj[i].push_back(j+100);
ans += dfs(1, 1);
adj[i].pop_back();
}
}
cout << ans;
}
Compilation message
startrek.cpp: In function 'long long int custompow(long long int, long long int)':
startrek.cpp:28:24: error: 'mod' was not declared in this scope; did you mean 'modf'?
28 | for(;y;y>>=1,x=x*x%mod) if(y&1) res = res*x%mod;
| ^~~
| modf
