답안 #31647 :: oj.uz

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
31647	2017-08-30T08:40:56 Z	cheater2k	구슬과 끈 (APIO14_beads)	C++14	57 / 100	280 ms	24208 KB

beads

#include <bits/stdc++.h>
using namespace std;

const int N = 200010;
const int inf = 1e9 + 12345;

int n;
int f[N][2], g[N][2];
vector < pair<int,int> > G[N], ch[N];
int ans;

void dfs(int u, int p) {
	for (auto edge: G[u]) if (edge.second != p) {
		dfs(edge.second, u);
		ch[u].push_back(edge);
	}
	f[u][1] = -inf;
	f[u][0] = 0;
	for (auto edge: ch[u]) {
		f[u][0] += max(f[edge.second][0], f[edge.second][1] + edge.first);
	}
	for (auto edge: ch[u]) {
		int mx = f[u][0];
		mx -= max(f[edge.second][0], f[edge.second][1] + edge.first);
		mx += (f[edge.second][0] + edge.first);
		f[u][1] = max(f[u][1], mx);
	}
}

void re_dfs(int u, int p) {
	ans = max(ans, g[u][0] + f[u][0]);
	//cerr << "redfs " << u << ' ' << f[u][0] + g[u][0] << ' ' << f[u][1] + g[u][1] << endl;

	// prepare
	vector <int> L(ch[u].size() + 2, -inf);
	vector <int> R(ch[u].size() + 2, -inf);

	for (int i = 0; i < (int)ch[u].size(); ++i) {
		pair<int,int> edge = ch[u][i];
		L[i + 1] = max(L[i], f[u][0] - max(f[edge.second][0], f[edge.second][1] + edge.first) + (f[edge.second][0] + edge.first));
	}
	for (int i = (int)ch[u].size() - 1; i >= 0; --i) {
		pair<int,int> edge = ch[u][i];
		R[i] = max(R[i + 1], f[u][0] - max(f[edge.second][0], f[edge.second][1] + edge.first) + (f[edge.second][0] + edge.first));
	}

	// solve
	for (int i = 0; i < (int)ch[u].size(); ++i) {
		int v = ch[u][i].second, w = ch[u][i].first;
		int cost = max(f[v][0], f[v][1] + w);
		int fu0 = f[u][0] - cost;
		int fu1 = max(L[i], R[i + 1]) - cost;
		g[v][0] = 0, g[v][1] = -inf;
		// g[v][0]
		g[v][0] = max(g[v][0], fu0 + g[u][0]);
		g[v][0] = max(g[v][0], fu1 + g[u][0] + w);
		g[v][0] = max(g[v][0], fu0 + g[u][1] + w);

		// g[v][1]
		g[v][1] = max(g[v][1], g[u][0] + fu0 + w);

		re_dfs(v, u);
	}
}

int main() {
	ios_base::sync_with_stdio(false); cin.tie(0);
	cin >> n;
	for (int i = 1; i < n; ++i) {
		int u, v, w; cin >> u >> v >> w;
		G[u].push_back(make_pair(w,v)); G[v].push_back(make_pair(w,u));
	}

	dfs(1,1);
	g[1][1] = -inf;
	re_dfs(1,1);

	cout << ans << endl;
}

Subtask #1
13.0 / 13.0

#	결과	실행 시간	메모리	Grader output
1	Correct	10 ms	9728 KB	Output is correct
2	Correct	10 ms	9728 KB	Output is correct
3	Correct	10 ms	9728 KB	Output is correct
4	Correct	10 ms	9728 KB	Output is correct
5	Correct	10 ms	9728 KB	Output is correct
6	Correct	10 ms	9728 KB	Output is correct
7	Correct	9 ms	9728 KB	Output is correct
8	Correct	9 ms	9728 KB	Output is correct
9	Correct	9 ms	9728 KB	Output is correct
10	Correct	10 ms	9728 KB	Output is correct
11	Correct	12 ms	9728 KB	Output is correct
12	Correct	10 ms	9728 KB	Output is correct

Subtask #2
15.0 / 15.0

#	결과	실행 시간	메모리	Grader output
1	Correct	10 ms	9728 KB	Output is correct
2	Correct	10 ms	9728 KB	Output is correct
3	Correct	10 ms	9728 KB	Output is correct
4	Correct	10 ms	9728 KB	Output is correct
5	Correct	10 ms	9728 KB	Output is correct
6	Correct	10 ms	9728 KB	Output is correct
7	Correct	9 ms	9728 KB	Output is correct
8	Correct	9 ms	9728 KB	Output is correct
9	Correct	9 ms	9728 KB	Output is correct
10	Correct	10 ms	9728 KB	Output is correct
11	Correct	12 ms	9728 KB	Output is correct
12	Correct	10 ms	9728 KB	Output is correct
13	Correct	10 ms	9728 KB	Output is correct
14	Correct	10 ms	9728 KB	Output is correct
15	Correct	10 ms	9728 KB	Output is correct
16	Correct	11 ms	9728 KB	Output is correct
17	Correct	10 ms	9728 KB	Output is correct
18	Correct	10 ms	9728 KB	Output is correct
19	Correct	10 ms	9856 KB	Output is correct
20	Correct	11 ms	9728 KB	Output is correct
21	Correct	10 ms	9728 KB	Output is correct
22	Correct	10 ms	9728 KB	Output is correct

Subtask #3
29.0 / 29.0

#	결과	실행 시간	메모리	Grader output
1	Correct	10 ms	9728 KB	Output is correct
2	Correct	10 ms	9728 KB	Output is correct
3	Correct	10 ms	9728 KB	Output is correct
4	Correct	10 ms	9728 KB	Output is correct
5	Correct	10 ms	9728 KB	Output is correct
6	Correct	10 ms	9728 KB	Output is correct
7	Correct	9 ms	9728 KB	Output is correct
8	Correct	9 ms	9728 KB	Output is correct
9	Correct	9 ms	9728 KB	Output is correct
10	Correct	10 ms	9728 KB	Output is correct
11	Correct	12 ms	9728 KB	Output is correct
12	Correct	10 ms	9728 KB	Output is correct
13	Correct	10 ms	9728 KB	Output is correct
14	Correct	10 ms	9728 KB	Output is correct
15	Correct	10 ms	9728 KB	Output is correct
16	Correct	11 ms	9728 KB	Output is correct
17	Correct	10 ms	9728 KB	Output is correct
18	Correct	10 ms	9728 KB	Output is correct
19	Correct	10 ms	9856 KB	Output is correct
20	Correct	11 ms	9728 KB	Output is correct
21	Correct	10 ms	9728 KB	Output is correct
22	Correct	10 ms	9728 KB	Output is correct
23	Correct	13 ms	10112 KB	Output is correct
24	Correct	13 ms	10112 KB	Output is correct
25	Correct	14 ms	10112 KB	Output is correct
26	Correct	16 ms	10496 KB	Output is correct
27	Correct	16 ms	10496 KB	Output is correct
28	Correct	15 ms	10496 KB	Output is correct
29	Correct	15 ms	10496 KB	Output is correct
30	Correct	15 ms	10496 KB	Output is correct
31	Correct	16 ms	11136 KB	Output is correct

Subtask #4
0 / 43.0

#	결과	실행 시간	메모리	Grader output
1	Correct	10 ms	9728 KB	Output is correct
2	Correct	10 ms	9728 KB	Output is correct
3	Correct	10 ms	9728 KB	Output is correct
4	Correct	10 ms	9728 KB	Output is correct
5	Correct	10 ms	9728 KB	Output is correct
6	Correct	10 ms	9728 KB	Output is correct
7	Correct	9 ms	9728 KB	Output is correct
8	Correct	9 ms	9728 KB	Output is correct
9	Correct	9 ms	9728 KB	Output is correct
10	Correct	10 ms	9728 KB	Output is correct
11	Correct	12 ms	9728 KB	Output is correct
12	Correct	10 ms	9728 KB	Output is correct
13	Correct	10 ms	9728 KB	Output is correct
14	Correct	10 ms	9728 KB	Output is correct
15	Correct	10 ms	9728 KB	Output is correct
16	Correct	11 ms	9728 KB	Output is correct
17	Correct	10 ms	9728 KB	Output is correct
18	Correct	10 ms	9728 KB	Output is correct
19	Correct	10 ms	9856 KB	Output is correct
20	Correct	11 ms	9728 KB	Output is correct
21	Correct	10 ms	9728 KB	Output is correct
22	Correct	10 ms	9728 KB	Output is correct
23	Correct	13 ms	10112 KB	Output is correct
24	Correct	13 ms	10112 KB	Output is correct
25	Correct	14 ms	10112 KB	Output is correct
26	Correct	16 ms	10496 KB	Output is correct
27	Correct	16 ms	10496 KB	Output is correct
28	Correct	15 ms	10496 KB	Output is correct
29	Correct	15 ms	10496 KB	Output is correct
30	Correct	15 ms	10496 KB	Output is correct
31	Correct	16 ms	11136 KB	Output is correct
32	Correct	56 ms	13372 KB	Output is correct
33	Correct	47 ms	13304 KB	Output is correct
34	Correct	59 ms	13304 KB	Output is correct
35	Incorrect	280 ms	24208 KB	Output isn't correct
36	Halted	0 ms	0 KB	-

답안 #31647

Compilation message

Subtask #1 13.0 / 13.0

Subtask #2 15.0 / 15.0

Subtask #3 29.0 / 29.0

Subtask #4 0 / 43.0

Subtask #1
13.0 / 13.0

Subtask #2
15.0 / 15.0

Subtask #3
29.0 / 29.0

Subtask #4
0 / 43.0