제출 #379709

#제출 시각아이디문제언어결과실행 시간메모리
379709VROOM_VARUNMergers (JOI19_mergers)C++14
100 / 100
2428 ms158200 KiB
/* ID: varunra2 LANG: C++ TASK: mergers */ #include <bits/stdc++.h> using namespace std; #ifdef DEBUG #include "lib/debug.h" #define debug(...) cerr << "[" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__) #define debug_arr(...) \ cerr << "[" << #__VA_ARGS__ << "]:", debug_arr(__VA_ARGS__) #pragma GCC diagnostic ignored "-Wsign-compare" //#pragma GCC diagnostic ignored "-Wunused-parameter" //#pragma GCC diagnostic ignored "-Wunused-variable" #else #define debug(...) 42 #endif #define EPS 1e-9 #define IN(A, B, C) assert(B <= A && A <= C) #define INF (int)1e9 #define MEM(a, b) memset(a, (b), sizeof(a)) #define MOD 1000000007 #define MP make_pair #define PB push_back #define all(cont) cont.begin(), cont.end() #define rall(cont) cont.end(), cont.begin() #define x first #define y second const double PI = acos(-1.0); typedef long long ll; typedef long double ld; typedef pair<int, int> PII; typedef map<int, int> MPII; typedef multiset<int> MSETI; typedef set<int> SETI; typedef set<string> SETS; typedef vector<int> VI; typedef vector<PII> VII; typedef vector<VI> VVI; typedef vector<string> VS; #define rep(i, a, b) for (int i = a; i < (b); ++i) #define trav(a, x) for (auto& a : x) #define sz(x) (int)(x).size() typedef pair<int, int> pii; typedef vector<int> vi; #pragma GCC diagnostic ignored "-Wsign-compare" // util functions int n, k; VVI adj; VII edg; VI color; VVI nodes; VI dep; VI par; VI mx; VI deg; void init() { adj.resize(n); color.resize(n); nodes.resize(k); dep.resize(n); mx.resize(n); deg.assign(n, 0); } struct lca { const int bits = 20; VVI lft; VI tin; VI tout; int tmr = 0; void dfs(int u, int v) { tin[u] = tmr++; lft[u][0] = v; for (int i = 1; i < bits; i++) { int to = lft[u][i - 1]; if (to == -1) lft[u][i] = -1; else lft[u][i] = lft[to][i - 1]; } trav(x, adj[u]) { if (x == v) continue; dfs(x, u); } tout[u] = tmr++; } void init() { tin.resize(n); tout.resize(n); lft.resize(n); trav(x, lft) x.resize(bits); dfs(0, -1); } bool isAnc(int u, int v) { if (u == -1) return true; if (v == -1) return false; return tin[u] <= tin[v] and tout[u] >= tout[v]; } int getLCA(int u, int v) { if (isAnc(u, v)) return u; if (isAnc(v, u)) return v; for (int i = bits - 1; i >= 0; i--) { if (!isAnc(lft[u][i], v)) { u = lft[u][i]; } } return lft[u][0]; } int getKthAnc(int u, int k, bool deb = false) { for (int i = bits - 1; i >= 0; i--) { if (k & (1 << i)) { if (deb) debug(u, lft[u][i], i); u = lft[u][i]; } } return u; } } lcaa; void dfs_dep(int u, int v) { if (v == -1) dep[u] = 0; trav(x, adj[u]) { if (x == v) continue; dep[x] = dep[u] + 1; dfs_dep(x, u); } } void dfs_mx(int u, int v) { trav(x, adj[u]) { if (x == v) continue; dfs_mx(x, u); mx[u] = min(mx[u], mx[x]); } } void checking(int u, int v, VI& vals) { for (auto& x : adj[u]) { if (x == v) continue; if (vals[x] != vals[u] and lcaa.isAnc(vals[x], vals[u])) assert(false); } trav(x, adj[u]) { if (x != v) checking(x, u, vals); } } void dfs_vals(int u, int v, VI& vals) { vals[u] = vals[vals[u]]; for (auto& x : adj[u]) { if (x == v) continue; dfs_vals(x, u, vals); } } int main() { // #ifndef ONLINE_JUDGE // freopen("mergers.in", "r", stdin); // freopen("mergers.out", "w", stdout); // #endif cin.sync_with_stdio(0); cin.tie(0); cin >> n >> k; if (n == 1) { cout << "0\n"; return 0; } init(); for (int i = 0; i < n - 1; i++) { int u, v; cin >> u >> v; u--, v--; adj[u].PB(v); adj[v].PB(u); edg.PB(MP(u, v)); } for (int i = 0; i < n; i++) { int col; cin >> col; col--; nodes[col].PB(i); color[i] = col; } dfs_dep(0, -1); mx = dep; lcaa.init(); for (int i = 0; i < k; i++) { int pt = nodes[i][0]; for (int j = 1; j < sz(nodes[i]); j++) { int u = pt; int v = nodes[i][j]; int lca = lcaa.getLCA(u, v); pt = lca; } for (int j = 0; j < sz(nodes[i]); j++) { mx[nodes[i][j]] = min(mx[nodes[i][j]], dep[pt]); } } dfs_mx(0, -1); VI vals(n); for (int i = 0; i < n; i++) { vals[i] = lcaa.getKthAnc(i, dep[i] - mx[i]); } dfs_vals(0, -1, vals); trav(x, edg) { int u = vals[x.x]; int v = vals[x.y]; if (u != v) { // debug(u, v, x.x, x.y); deg[u]++; deg[v]++; } } int ret = 0; for (int i = 0; i < n; i++) { if (deg[i] == 1) ret++; } cout << (ret + 1) / 2 << '\n'; checking(0, -1, vals); // [u, v, x.x, x.y]: 39 0 86 44 // [u, v, x.x, x.y]: 39 0 90 68 // if (n >= 100) { // debug(dep[86], dep[44], dep[90], dep[68]); // debug(lcaa.tin[86], lcaa.tout[86]); // debug(lcaa.tin[44], lcaa.tout[44]); // debug(lcaa.tin[90], lcaa.tout[90]); // debug(lcaa.tin[68], lcaa.tout[68]); // debug(lcaa.getLCA(44, 68)); // } // debug(vals); // debug(mx); // debug(deg); return 0; }

컴파일 시 표준 에러 (stderr) 메시지

mergers.cpp: In member function 'int lca::getKthAnc(int, int, bool)':
mergers.cpp:19:20: warning: statement has no effect [-Wunused-value]
   19 | #define debug(...) 42
      |                    ^~
mergers.cpp:127:18: note: in expansion of macro 'debug'
  127 |         if (deb) debug(u, lft[u][i], i);
      |                  ^~~~~
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