oj.uz

답안 #642085

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
642085 2022-09-18T12:39:01 Z vovamr Transport (COCI19_transport) C++17
91 / 130
 1000 ms 21224 KB 
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#define fi first
#define se second
#define ll long long
#define ld long double
#define sz(x) ((int)(x).size())
#define all(x) 	(x).begin(), (x).end()
#define pb push_back
#define mpp make_pair
#define ve vector
using namespace std;
using namespace __gnu_pbds;
template<class T> using oset = tree<T,null_type,less_equal<T>,rb_tree_tag,tree_order_statistics_node_update>;
const ll inf = 1e18; const int iinf = 1e9;
typedef pair<ll, ll> pll;
typedef pair<int, int> pii;
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
template <typename T> inline bool chmin(T& a, T b) { return (a > b ? a = b, 1 : 0); }
template <typename T> inline bool chmax(T& a, T b) { return (a < b ? a = b, 1 : 0); }

const int N = 1e5 + 10;
ve<pii> gr[N];
int sz[N], used[N], a[N];
inline void dfs1(int v, int p) {
	sz[v] = 1;
	for (auto &[to, w] : gr[v]) {
		if (used[to] || to == p) continue;
		dfs1(to, v); sz[v] += sz[to];
	}
}
inline int centroid(int v, int p, int n) {
	for (auto &[to, w] : gr[v]) {
		if (used[to] || to == p || sz[to] <= n / 2) continue;
		return centroid(to, v, n);
	} return v;
}

ll ans = 0;

int PTR = 0;
pll al[N];

inline void dfs(int v, int p, ll cur_sum, ll mn_sum) {

	if (mn_sum >= 0) ++ans;

	al[PTR++] = {cur_sum, mn_sum};
	for (auto &[to, w] : gr[v]) {
		if (to == p || used[to]) continue;

		ll s = cur_sum + a[v] - w;
		dfs(to, v, s, min(mn_sum, s));
	}
}

ll t[4 * N], p[4 * N];
inline int mg(const ll &a, const ll &b) { return min(a, b); }
inline void mg(const int &v) { t[v] = mg(t[2 * v + 1], t[2 * v + 2]); }

inline void push(int v) {
	if (!p[v]) return;
	for (int u : {2 * v + 1, 2 * v + 2}) {
		t[u] += p[v], p[u] += p[v];
	}
	p[v] = 0;
}
inline void upd(int v, int vl, int vr, int l, int r, ll x) {
	if (l > r) return;
	else if (vl == l && vr == r) {
		t[v] += x, p[v] += x;
		return;
	}
	push(v);
	int m = vl + vr >> 1;
	upd(2 * v + 1, vl, m, l, min(r, m), x);
	upd(2 * v + 2, m + 1, vr, max(l, m + 1), r, x);
	mg(v);
}
inline ll get(int v, int vl, int vr, int l, int r) {
	if (l > r) return inf;
	else if (vl == l && vr == r) return t[v];
	push(v);
	int m = vl + vr >> 1;
	return min(get(2 * v + 1, vl, m, l, min(r, m)),
		get(2 * v + 2, m + 1, vr, max(l, m + 1), r));
}

int n;

oset<ll> sums;

inline void dfs2(int v, int p, int pw, int cnt) {
	upd(0, 0, n - 1, 0, cnt - 1, a[v] - pw);

	ll mn_sum = get(0, 0, n - 1, 0, cnt);
	ll tot = get(0, 0, n - 1, 0, 0);

	if (mn_sum >= 0) {
		ans += 1 + sz(sums) - sums.order_of_key(-tot);
	}

	// number of [sum, mn_sum] s.t.
	// mn_sum + tot >= 0 => mn_sum >= -tot

	for (auto &[to, w] : gr[v]) {
		if (to == p || used[to]) continue;
		dfs2(to, v, w, cnt + 1);
	}

	upd(0, 0, n - 1, 0, cnt - 1, pw - a[v]);
}

inline void cd(int v, int p) {
	used[v] = 1; dfs1(v, p);

	PTR = 0;
	for (auto &[to, w] : gr[v]) {
		if (to == p || used[to]) continue;
		dfs(to, v, a[v] - w, a[v] - w);
	}

	sums.clear();
	for (int i = 0; i < PTR; ++i) {
		auto &[sum, mn_sum] = al[i];
		sums.insert(mn_sum);
	}

	int pos = 0;
	for (auto &[to, w] : gr[v]) {
		if (to == p || used[to]) continue;
		for (int i = pos; i < pos + sz[to]; ++i) {
			auto &[sum, mn_sum] = al[i];
			sums.erase(sums.lower_bound(mn_sum - 1));
		}

		dfs2(to, v, w, 1);

		for (int i = pos; i < pos + sz[to]; ++i) {
			auto &[sum, mn_sum] = al[i];
			sums.insert(mn_sum);
		}
		pos += sz[to];
	}

	for (auto &[to, w] : gr[v]) {
		if (to == p || used[to]) continue;
		int c = centroid(to, v, sz[to]);
		cd(c, v);
	}
}

inline void solve() {

	cin >> n;
	for (int i = 0; i < n; ++i) cin >> a[i];
	for (int i = 1; i < n; ++i) {
		int v, u, w;
		cin >> v >> u >> w, --v, --u;
		gr[v].pb({u, w}), gr[u].pb({v, w});
	}

	dfs1(0, 0);
	int c = centroid(0, 0, n);

	cd(c, c);
	cout << ans;
}

signed main() {
	ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
	int q = 1; // cin >> q;
	while (q--) solve();
	cerr << fixed << setprecision(3) << "Time execution: " << (double)clock() / CLOCKS_PER_SEC << endl;
}

Compilation message

transport.cpp: In function 'void upd(int, int, int, int, int, long long int)':
transport.cpp:76:13: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   76 |  int m = vl + vr >> 1;
      |          ~~~^~~~
transport.cpp: In function 'long long int get(int, int, int, int, int)':
transport.cpp:85:13: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   85 |  int m = vl + vr >> 1;
      |          ~~~^~~~

Subtask #1
13.0 / 13.0

# 결과 실행 시간 메모리 Grader output
1 Correct 19 ms 3156 KB Output is correct
2 Correct 19 ms 3332 KB Output is correct

Subtask #2
13.0 / 13.0

# 결과 실행 시간 메모리 Grader output
1 Correct 31 ms 3580 KB Output is correct
2 Correct 44 ms 3848 KB Output is correct

Subtask #3
0 / 13.0

# 결과 실행 시간 메모리 Grader output
1 Correct 569 ms 12560 KB Output is correct
2 Incorrect 484 ms 11672 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #4
13.0 / 13.0

# 결과 실행 시간 메모리 Grader output
1 Correct 811 ms 16084 KB Output is correct
2 Correct 884 ms 18248 KB Output is correct

Subtask #5
0 / 13.0

# 결과 실행 시간 메모리 Grader output
1 Execution timed out 1085 ms 21224 KB Time limit exceeded
2 Halted 0 ms 0 KB -

Subtask #6
13.0 / 13.0

# 결과 실행 시간 메모리 Grader output
1 Correct 278 ms 6868 KB Output is correct
2 Correct 162 ms 6360 KB Output is correct

Subtask #7
13.0 / 13.0

# 결과 실행 시간 메모리 Grader output
1 Correct 245 ms 9812 KB Output is correct
2 Correct 448 ms 9080 KB Output is correct

Subtask #8
13.0 / 13.0

# 결과 실행 시간 메모리 Grader output
1 Correct 526 ms 11924 KB Output is correct
2 Correct 568 ms 12548 KB Output is correct

Subtask #9
13.0 / 13.0

# 결과 실행 시간 메모리 Grader output
1 Correct 773 ms 14668 KB Output is correct
2 Correct 744 ms 15052 KB Output is correct

Subtask #10
0 / 13.0

# 결과 실행 시간 메모리 Grader output
1 Execution timed out 1077 ms 18396 KB Time limit exceeded
2 Halted 0 ms 0 KB -