/CLERVT_setter.cpp Secret
Created
April 15, 2018 01:04
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#include <bits/stdc++.h> | |
using namespace std; | |
const int MAX_N = 1e5 + 5; | |
const int MAX_K = 27; | |
int N, K, Q; | |
vector<int> g[MAX_N]; | |
set<int> Gset; | |
vector<int> G; | |
map<int, int> pos; | |
int dist[MAX_K + 1][MAX_K + 1]; | |
int dp[1 << MAX_K], ans; | |
void dfs(int src, int u, int p, int d) { | |
if (Gset.count(u)) { | |
if (src == K) { | |
pos[u] = G.size(); | |
G.push_back(u); | |
} | |
dist[src][pos[u]] = dist[pos[u]][src] = d; | |
} | |
for (int v : g[u]) if (v != p) | |
dfs(src, v, u, d + 1); | |
} | |
void solve() { | |
dfs(K, 1, 0, 0); | |
for (int i = 0; i < K; i++) | |
dfs(i, G[i], 0, 0); | |
ans = N - 1; | |
for (int mask = 1; mask < (1 << K); mask++) { | |
int last = __builtin_ctz(mask); | |
int m = mask ^ (1 << last); | |
if (m == 0) { | |
dp[mask] = dist[K][last]; | |
ans ^= N - 1 - dp[mask]; | |
continue; | |
} | |
int last2 = __builtin_ctz(m); | |
dp[mask] = dp[m] + dist[last][last2]; | |
ans ^= N - 1 - (dp[mask] + dist[K][last]) / 2; | |
} | |
} | |
int main() { | |
ios_base::sync_with_stdio(false); cin.tie(NULL); | |
cin >> N; | |
for (int i = 0; i < N - 1; i++) { | |
int u, v; cin >> u >> v; | |
g[u].push_back(v); | |
g[v].push_back(u); | |
} | |
cin >> K; | |
for (int i = 0; i < K; i++) { | |
int x; cin >> x; | |
Gset.insert(x); | |
} | |
solve(); | |
cout << ans << "\n"; | |
return 0; | |
} |
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