답안 #265497

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
265497	2020-08-14T22:24:47 Z	square1001	구슬과 끈 (APIO14_beads)	C++14	28 / 100	1000 ms	768 KB

beads

#include <vector>
#include <iostream>
#include <algorithm>
#include <functional>
using namespace std;
const long long inf = 1LL << 40;
int main() {
	// step #1. read input
	cin.tie(0);
	ios_base::sync_with_stdio(false);
	int N;
	cin >> N;
	vector<int> ga(N - 1), gb(N - 1); vector<long long> gw(N - 1);
	for(int i = 0; i < N - 1; ++i) {
		cin >> ga[i] >> gb[i] >> gw[i];
		--ga[i], --gb[i];
	}
	// step #2. construct a graph
	vector<int> sep(N + 1);
	for(int i = 0; i < N - 1; ++i) {
		++sep[ga[i] + 1];
		++sep[gb[i] + 1];
	}
	for(int i = 0; i < N; ++i) {
		sep[i + 1] += sep[i];
	}
	vector<int> ctr(sep);
	vector<int> to(2 * N - 2); vector<long long> cost(2 * N - 2);
	for(int i = 0; i < N - 1; ++i) {
		to[ctr[ga[i]]] = gb[i]; cost[ctr[ga[i]]++] = gw[i];
		to[ctr[gb[i]]] = ga[i]; cost[ctr[gb[i]]++] = gw[i];
	}
	// step #3. calculation
	function<pair<long long, long long>(int, int)> solve = [&](int pos, int pre) {
		// returns = (no mid-blue, one mid-blue)
		long long sumcost = 0, delta = -inf;
		for(int i = sep[pos]; i < sep[pos + 1]; ++i) {
			if(to[i] == pre) continue;
			pair<long long, long long> res = solve(to[i], pos);
			sumcost += max(res.first, res.second + cost[i]);
			delta = max(delta, cost[i] - max(res.second + cost[i] - res.first, 0LL));
		}
		return make_pair(sumcost, sumcost + delta);
	};
	long long ans = 0;
	for(int i = 0; i < N; ++i) {
		pair<long long, long long> res = solve(i, -1);
		ans = max(ans, res.first);
	}
	// step #4. print the answer
	cout << ans << endl;
	return 0;
}

Subtask #1

13.0 / 13.0

#	결과	실행 시간	메모리	Grader output
1	Correct	0 ms	384 KB	Output is correct
2	Correct	1 ms	384 KB	Output is correct
3	Correct	0 ms	384 KB	Output is correct
4	Correct	1 ms	384 KB	Output is correct
5	Correct	0 ms	384 KB	Output is correct
6	Correct	0 ms	384 KB	Output is correct
7	Correct	0 ms	384 KB	Output is correct
8	Correct	1 ms	384 KB	Output is correct
9	Correct	0 ms	384 KB	Output is correct
10	Correct	0 ms	384 KB	Output is correct
11	Correct	1 ms	384 KB	Output is correct
12	Correct	1 ms	384 KB	Output is correct

Subtask #2

15.0 / 15.0

#	결과	실행 시간	메모리	Grader output
1	Correct	0 ms	384 KB	Output is correct
2	Correct	1 ms	384 KB	Output is correct
3	Correct	0 ms	384 KB	Output is correct
4	Correct	1 ms	384 KB	Output is correct
5	Correct	0 ms	384 KB	Output is correct
6	Correct	0 ms	384 KB	Output is correct
7	Correct	0 ms	384 KB	Output is correct
8	Correct	1 ms	384 KB	Output is correct
9	Correct	0 ms	384 KB	Output is correct
10	Correct	0 ms	384 KB	Output is correct
11	Correct	1 ms	384 KB	Output is correct
12	Correct	1 ms	384 KB	Output is correct
13	Correct	1 ms	384 KB	Output is correct
14	Correct	1 ms	384 KB	Output is correct
15	Correct	1 ms	384 KB	Output is correct
16	Correct	1 ms	384 KB	Output is correct
17	Correct	1 ms	384 KB	Output is correct
18	Correct	1 ms	384 KB	Output is correct
19	Correct	1 ms	512 KB	Output is correct
20	Correct	1 ms	384 KB	Output is correct
21	Correct	2 ms	384 KB	Output is correct
22	Correct	1 ms	384 KB	Output is correct

Subtask #3

0 / 29.0

#	결과	실행 시간	메모리	Grader output
1	Correct	0 ms	384 KB	Output is correct
2	Correct	1 ms	384 KB	Output is correct
3	Correct	0 ms	384 KB	Output is correct
4	Correct	1 ms	384 KB	Output is correct
5	Correct	0 ms	384 KB	Output is correct
6	Correct	0 ms	384 KB	Output is correct
7	Correct	0 ms	384 KB	Output is correct
8	Correct	1 ms	384 KB	Output is correct
9	Correct	0 ms	384 KB	Output is correct
10	Correct	0 ms	384 KB	Output is correct
11	Correct	1 ms	384 KB	Output is correct
12	Correct	1 ms	384 KB	Output is correct
13	Correct	1 ms	384 KB	Output is correct
14	Correct	1 ms	384 KB	Output is correct
15	Correct	1 ms	384 KB	Output is correct
16	Correct	1 ms	384 KB	Output is correct
17	Correct	1 ms	384 KB	Output is correct
18	Correct	1 ms	384 KB	Output is correct
19	Correct	1 ms	512 KB	Output is correct
20	Correct	1 ms	384 KB	Output is correct
21	Correct	2 ms	384 KB	Output is correct
22	Correct	1 ms	384 KB	Output is correct
23	Correct	611 ms	748 KB	Output is correct
24	Correct	602 ms	624 KB	Output is correct
25	Correct	603 ms	632 KB	Output is correct
26	Execution timed out	1050 ms	768 KB	Time limit exceeded
27	Halted	0 ms	0 KB	-

Subtask #4

0 / 43.0

#	결과	실행 시간	메모리	Grader output
1	Correct	0 ms	384 KB	Output is correct
2	Correct	1 ms	384 KB	Output is correct
3	Correct	0 ms	384 KB	Output is correct
4	Correct	1 ms	384 KB	Output is correct
5	Correct	0 ms	384 KB	Output is correct
6	Correct	0 ms	384 KB	Output is correct
7	Correct	0 ms	384 KB	Output is correct
8	Correct	1 ms	384 KB	Output is correct
9	Correct	0 ms	384 KB	Output is correct
10	Correct	0 ms	384 KB	Output is correct
11	Correct	1 ms	384 KB	Output is correct
12	Correct	1 ms	384 KB	Output is correct
13	Correct	1 ms	384 KB	Output is correct
14	Correct	1 ms	384 KB	Output is correct
15	Correct	1 ms	384 KB	Output is correct
16	Correct	1 ms	384 KB	Output is correct
17	Correct	1 ms	384 KB	Output is correct
18	Correct	1 ms	384 KB	Output is correct
19	Correct	1 ms	512 KB	Output is correct
20	Correct	1 ms	384 KB	Output is correct
21	Correct	2 ms	384 KB	Output is correct
22	Correct	1 ms	384 KB	Output is correct
23	Correct	611 ms	748 KB	Output is correct
24	Correct	602 ms	624 KB	Output is correct
25	Correct	603 ms	632 KB	Output is correct
26	Execution timed out	1050 ms	768 KB	Time limit exceeded
27	Halted	0 ms	0 KB	-