제출 #1228691

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
1228691		avohado	Election Campaign (JOI15_election_campaign)	C++20	100 / 100	109 ms	40008 KiB

election_campaign

#include "bits/stdc++.h"

using namespace std;

#define ln "\n"
#define pb push_back
#define fi first
#define se second
#define all(x) (x).begin(), (x).end()
#define sz(x) ((int)(x).size())
#define int long long
const int mod = 1e9 + 7;
const int inf = 2e18;
const int N = 1e5 + 7;
int n, m, in[N], out[N], h[N], up[N][20], timer, dp[N][2];
vector<int> g[N];

struct BIT {
	vector<int> bit;
	int n;
	BIT() {}
	BIT(int n) : n(n) {
		bit.resize(n + 5, 0);
	}
	void update(int u, int x) {
		for(u; u <= n; u += (u & -u)) bit[u] += x;
	}
	void update(int l, int r, int x) {
		update(l, x);
		update(r + 1, -x);
	}
	int get(int u) {
		int ans = 0;
		for(u; u > 0; u -= (u & -u)) ans += bit[u];
		return ans;
	}
} bit;

int lca(int u, int v) {
	if(h[u] < h[v]) swap(u, v);
	int k = h[u] - h[v];
	for(int i = 0; (1 << i) <= k; i++) {
		if(k >> i & 1) u = up[u][i];
	}
	if(u == v) return u;
	for(int i = 19; i >= 0; i--) {
		if(up[u][i] != up[v][i]) {
			u = up[u][i];
			v = up[v][i];
		}
	}
	return up[u][0];
}

struct query {
	int u, v, c;
};

vector<query> ev[N];

void pre_dfs(int u, int p) {
	for(int i = 1; i < 20; i++) up[u][i] = up[up[u][i - 1]][i - 1];
	in[u] = ++timer;
	for(int v : g[u]) {
		if(v == p) continue;
		h[v] = h[u] + 1;
		up[v][0] = u;
		pre_dfs(v, u);
	}
	out[u] = timer;
}

void dfs(int u, int p) {
	dp[u][0] = 0;
	dp[u][1] = -inf;
	for(int v : g[u]) {
		if(v == p) continue;
		dfs(v, u);
		dp[u][0] += max(dp[v][0], dp[v][1]);
	}
	for(auto x : ev[u]) {
		int a = x.u, b = x.v, c = x.c;
		dp[u][1] = max(dp[u][1], dp[u][0] + bit.get(in[a]) + bit.get(in[b]) + c);
	}
	// cout << u << ' ' << dp[u][0] << ' ' << dp[u][1] << ln;
	bit.update(in[u], out[u], dp[u][0] - max(dp[u][0], dp[u][1]));
}

signed main() {
	cin.tie(0) -> sync_with_stdio(0);
	#define task ""
	if(fopen(task ".INP", "r")) {
		freopen(task ".INP", "r", stdin);
		freopen(task ".OUT", "w", stdout);
	}
	cin >> n;
	for(int i = 1; i < n; i++) {
		int u, v; cin >> u >> v;
		g[u].pb(v);
		g[v].pb(u);
	}
	pre_dfs(1, 0);
	cin >> m;
	for(int i = 1; i <= m; i++) {
		int u, v, c; cin >> u >> v >> c;
		int p = lca(u, v);
		// cout << u << ' ' << v << ' ' << p << ln;
		ev[p].pb({u, v, c});
	}
	bit = BIT(n);
	dfs(1, 0);
	// for(int i = 1; i <= n; i++) {
	// 	cout << dp[i][0] << ' ' << dp[i][1] << ln;
	// }
	cout << max(dp[1][0], dp[1][1]) << ln;
  cerr << "\nTime: " << clock() * 1000 / CLOCKS_PER_SEC;
}

컴파일 시 표준 에러 (stderr) 메시지

election_campaign.cpp: In function 'int main()':
election_campaign.cpp:93:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   93 |                 freopen(task ".INP", "r", stdin);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
election_campaign.cpp:94:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   94 |                 freopen(task ".OUT", "w", stdout);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 5 / 5
• Subtask 3: 5 / 5
• Subtask 4: 30 / 30
• Subtask 5: 10 / 10
• Subtask 6: 40 / 40