Submission #549008

#TimeUsernameProblemLanguageResultExecution timeMemory
549008SmolBrainUsmjeri (COCI17_usmjeri)C++17
0 / 140
110 ms262144 KiB
// Om Namah Shivaya // GM in 109 days #include <bits/stdc++.h> #include <ext/pb_ds/assoc_container.hpp> #include <ext/pb_ds/tree_policy.hpp> using namespace std; using namespace __gnu_pbds; template <class T> using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>; typedef long long int ll; typedef long double ld; typedef pair<int, int> pii; typedef pair<ll, ll> pll; #define fastio ios_base::sync_with_stdio(false); cin.tie(NULL) #define endl '\n' #define pb push_back #define conts continue #define all(a) a.begin(), a.end() #define rall(a) a.rbegin(), a.rend() #define yes cout << "YES" << endl #define no cout << "NO" << endl #define ff first #define ss second #define ceil2(x,y) ((x+y-1) / (y)) #define sz(a) a.size() #define setbits(x) __builtin_popcountll(x) #ifndef ONLINE_JUDGE #define debug(x) cout << #x <<" = "; print(x); cout << endl #else #define debug(x) #endif #define rep(i,n) for(int i = 0; i < n; ++i) #define rep1(i,n) for(int i = 1; i <= n; ++i) #define rev(i,s,e) for(int i = s; i >= e; --i) #define trav(i,a) for(auto &i : a) bool iseven(ll n) {if ((n & 1) == 0) return true; return false;} void print(ll t) {cout << t;} void print(int t) {cout << t;} void print(string t) {cout << t;} void print(char t) {cout << t;} void print(double t) {cout << t;} void print(ld t) {cout << t;} template <class T, class V> void print(pair <T, V> p); template <class T> void print(vector <T> v); template <class T> void print(set <T> v); template <class T, class V> void print(map <T, V> v); template <class T> void print(multiset <T> v); template <class T, class V> void print(pair <T, V> p) {cout << "{"; print(p.ff); cout << ","; print(p.ss); cout << "}";} template <class T> void print(vector <T> v) {cout << "[ "; for (T i : v) {print(i); cout << " ";} cout << "]";} template <class T> void print(set <T> v) {cout << "[ "; for (T i : v) {print(i); cout << " ";} cout << "]";} template <class T> void print(multiset <T> v) {cout << "[ "; for (T i : v) {print(i); cout << " ";} cout << "]";} template <class T, class V> void print(map <T, V> v) {cout << "[ "; for (auto i : v) {print(i); cout << " ";} cout << "]";} template<typename T> void amin(T &a, T b) { a = min(a, b); } template<typename T> void amax(T &a, T b) { a = max(a, b); } void usaco(string filename) { freopen((filename + ".in").c_str(), "r", stdin); freopen((filename + ".out").c_str(), "w", stdout); } const int MOD = 1e9 + 7; const int maxn = 3e5 + 5; const int inf1 = 1e9 + 5; const ll inf2 = ll(1e18) + 5; vector<int> adj[maxn]; struct lca_algo { // LCA template (for graphs with 1-based indexing) int LOG = 1; vector<int> depth; vector<vector<int>> up; lca_algo() { } lca_algo(int n) { lca_init(n); } void lca_init(int n) { while ((1 << LOG) < n) LOG++; up = vector<vector<int>>(n + 1, vector<int>(LOG)); depth = vector<int>(n + 1); lca_dfs(1, -1); } void lca_dfs(int node, int par) { trav(child, adj[node]) { if (child == par) conts; up[child][0] = node; rep1(j, LOG - 1) { up[child][j] = up[up[child][j - 1]][j - 1]; } depth[child] = depth[node] + 1; lca_dfs(child, node); } } int lift(int u, int k) { rep(j, LOG) { if (k & (1 << j)) { u = up[u][j]; } } return u; } int query(int u, int v) { if (depth[u] < depth[v]) swap(u, v); int k = depth[u] - depth[v]; u = lift(u, k); if (u == v) return u; rev(j, LOG - 1, 0) { if (up[u][j] != up[v][j]) { u = up[u][j]; v = up[v][j]; } } u = up[u][0]; return u; } }; vector<int> parent(maxn, -1); void dfs(int node, int par) { parent[node] = par; trav(child, adj[node]) { if (child == par) conts; dfs(child, node); } } void solve(int test_case) { int n, m; cin >> n >> m; int edge[n + 1][n + 1]; memset(edge, 0, sizeof edge); rep1(i, n - 1) { int u, v; cin >> u >> v; adj[u].pb(v), adj[v].pb(u); } lca_algo LCA(n); dfs(1, -1); int ans = 1; while (m--) { int u, v; cin >> u >> v; int ou = u, ov = v; int lca = LCA.query(u, v); int one1 = 0, two1 = 0, one2 = 0, two2 = 0; while (u != lca) { int p = parent[u]; if (edge[u][p] == 1) one1++; else if (edge[u][p] == 2) two1++; u = p; } while (v != lca) { int p = parent[v]; if (edge[v][p] == 1) one2++; else if (edge[v][p] == 2) two2++; v = p; } u = ou, v = ov; if (one1 == 0 and one2 == 0 and two1 == 0 and two2 == 0) { ans = (ans * 2) % MOD; while (u != lca) { int p = parent[u]; if (!edge[u][p]) { edge[u][p] = 1; edge[p][u] = 1; } u = p; } while (v != lca) { int p = parent[v]; if (!edge[v][p]) { edge[v][p] = 2; edge[p][v] = 2; } v = p; } } else { if ((one1 and one2) or (two1 and two2)) { cout << 0 << endl; return; } if (one1 or two2) { while (u != lca) { int p = parent[u]; if (!edge[u][p]) { edge[u][p] = 1; edge[p][u] = 1; } u = p; } while (v != lca) { int p = parent[v]; if (!edge[v][p]) { edge[v][p] = 2; edge[p][v] = 2; } v = p; } } else { while (u != lca) { int p = parent[u]; if (!edge[u][p]) { edge[u][p] = 2; edge[p][u] = 2; } u = p; } while (v != lca) { int p = parent[v]; if (!edge[v][p]) { edge[v][p] = 1; edge[p][v] = 1; } v = p; } } } } rep1(u, n) { trav(v, adj[u]) { if (u != parent[v]) conts; if (!edge[u][v]) { ans = (ans * 2) % MOD; } } } cout << ans << endl; } int main() { fastio; int t = 1; // cin >> t; rep1(i, t) { solve(i); } return 0; }

Compilation message (stderr)

usmjeri.cpp: In function 'void usaco(std::string)':
usmjeri.cpp:64:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   64 |     freopen((filename + ".in").c_str(), "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
usmjeri.cpp:65:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   65 |     freopen((filename + ".out").c_str(), "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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