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Submission #363143

# Submission time Handle Problem Language Result Execution time Memory
363143 2021-02-05T07:33:35 Z shivensinha4 Beads and wires (APIO14_beads) C++17
100 / 100
 228 ms 18016 KB 
#include "bits/stdc++.h"
using namespace std;
#define for_(i, s, e) for (int i = s; i < (int) e; i++)
#define for__(i, s, e) for (ll i = s; i < e; i++)
typedef long long ll;
typedef vector<int> vi;
typedef pair<int, int> ii;
//#define endl '\n'

const int MXN = 2e5, INF = 1e9;
vector<array<int, 2>> dp;
vector<vector<array<int, 2>>> adj;
int n, ans = 0;

void dfs(int p, int parent, int pe=0) {
	dp[p] = {0, 0};
	int v = 0;
	for (auto i: adj[p]) if (i[0] != parent) {
		dfs(i[0], p, i[1]);
		v = max(v, -dp[i[0]][0] + dp[i[0]][1] + i[1] + pe);
		dp[p][1] += dp[i[0]][0];
	}
	dp[p][0] = dp[p][1] + (p == parent ? 0 : v);
}

void reroot(int p, int parent) {
	array<int, 2> opt = {-INF, -INF}, pre = dp[p];
	
	if (parent != p) dp[p][1] += dp[parent][0];

	for (auto i: adj[p]) {
		int temp = -dp[i[0]][0] + dp[i[0]][1] + i[1];
		if (temp >= opt[0]) {
			swap(opt[0], opt[1]);
			opt[0] = temp;
		} else if (temp > opt[1]) opt[1] = temp;
	}
	
	ans = max(ans, dp[p][1]);
	
	for (auto i: adj[p]) if (i[0] != parent) {
		dp[p][1] -= dp[i[0]][0];
		dp[p][0] = dp[p][1];
		
		int temp = -dp[i[0]][0] + dp[i[0]][1] + i[1];
		if (temp == opt[0]) dp[p][0] += max(opt[1]+i[1], 0);
		else dp[p][0] += max(opt[0]+i[1], 0);
		
		reroot(i[0], p);
		
		dp[p][1] += dp[i[0]][0];
	}
	
	dp[p] = pre;
}

int main() {
#ifdef mlocal
	freopen("test.in", "r", stdin);
#endif
	
	ios_base::sync_with_stdio(false);
	cin.tie(0);
	
	cin >> n;
	dp.resize(n); adj.resize(n);
	for_(i, 0, n-1) {
		int a, b, w; cin >> a >> b >> w;
		a -= 1; b -= 1;
		adj[a].push_back({b, w}); adj[b].push_back({a, w});
	}
	
	dfs(0, 0, 0);
	reroot(0, 0);
	
	cout << ans << endl;
	
	
	return 0;
}

Subtask #1
13.0 / 13.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 364 KB Output is correct
2 Correct 1 ms 364 KB Output is correct
3 Correct 1 ms 364 KB Output is correct
4 Correct 1 ms 364 KB Output is correct
5 Correct 1 ms 364 KB Output is correct
6 Correct 1 ms 364 KB Output is correct
7 Correct 1 ms 364 KB Output is correct
8 Correct 1 ms 364 KB Output is correct
9 Correct 0 ms 364 KB Output is correct
10 Correct 0 ms 364 KB Output is correct
11 Correct 1 ms 364 KB Output is correct
12 Correct 1 ms 384 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 364 KB Output is correct
2 Correct 1 ms 364 KB Output is correct
3 Correct 1 ms 364 KB Output is correct
4 Correct 1 ms 364 KB Output is correct
5 Correct 1 ms 364 KB Output is correct
6 Correct 1 ms 364 KB Output is correct
7 Correct 1 ms 364 KB Output is correct
8 Correct 1 ms 364 KB Output is correct
9 Correct 0 ms 364 KB Output is correct
10 Correct 0 ms 364 KB Output is correct
11 Correct 1 ms 364 KB Output is correct
12 Correct 1 ms 384 KB Output is correct
13 Correct 1 ms 364 KB Output is correct
14 Correct 1 ms 364 KB Output is correct
15 Correct 1 ms 384 KB Output is correct
16 Correct 1 ms 364 KB Output is correct
17 Correct 1 ms 364 KB Output is correct
18 Correct 1 ms 364 KB Output is correct
19 Correct 1 ms 364 KB Output is correct
20 Correct 1 ms 364 KB Output is correct
21 Correct 1 ms 364 KB Output is correct
22 Correct 1 ms 364 KB Output is correct

Subtask #3
29.0 / 29.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 364 KB Output is correct
2 Correct 1 ms 364 KB Output is correct
3 Correct 1 ms 364 KB Output is correct
4 Correct 1 ms 364 KB Output is correct
5 Correct 1 ms 364 KB Output is correct
6 Correct 1 ms 364 KB Output is correct
7 Correct 1 ms 364 KB Output is correct
8 Correct 1 ms 364 KB Output is correct
9 Correct 0 ms 364 KB Output is correct
10 Correct 0 ms 364 KB Output is correct
11 Correct 1 ms 364 KB Output is correct
12 Correct 1 ms 384 KB Output is correct
13 Correct 1 ms 364 KB Output is correct
14 Correct 1 ms 364 KB Output is correct
15 Correct 1 ms 384 KB Output is correct
16 Correct 1 ms 364 KB Output is correct
17 Correct 1 ms 364 KB Output is correct
18 Correct 1 ms 364 KB Output is correct
19 Correct 1 ms 364 KB Output is correct
20 Correct 1 ms 364 KB Output is correct
21 Correct 1 ms 364 KB Output is correct
22 Correct 1 ms 364 KB Output is correct
23 Correct 3 ms 620 KB Output is correct
24 Correct 3 ms 620 KB Output is correct
25 Correct 3 ms 620 KB Output is correct
26 Correct 6 ms 1004 KB Output is correct
27 Correct 7 ms 1004 KB Output is correct
28 Correct 5 ms 1132 KB Output is correct
29 Correct 5 ms 1004 KB Output is correct
30 Correct 5 ms 1004 KB Output is correct
31 Correct 6 ms 1388 KB Output is correct

Subtask #4
43.0 / 43.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 364 KB Output is correct
2 Correct 1 ms 364 KB Output is correct
3 Correct 1 ms 364 KB Output is correct
4 Correct 1 ms 364 KB Output is correct
5 Correct 1 ms 364 KB Output is correct
6 Correct 1 ms 364 KB Output is correct
7 Correct 1 ms 364 KB Output is correct
8 Correct 1 ms 364 KB Output is correct
9 Correct 0 ms 364 KB Output is correct
10 Correct 0 ms 364 KB Output is correct
11 Correct 1 ms 364 KB Output is correct
12 Correct 1 ms 384 KB Output is correct
13 Correct 1 ms 364 KB Output is correct
14 Correct 1 ms 364 KB Output is correct
15 Correct 1 ms 384 KB Output is correct
16 Correct 1 ms 364 KB Output is correct
17 Correct 1 ms 364 KB Output is correct
18 Correct 1 ms 364 KB Output is correct
19 Correct 1 ms 364 KB Output is correct
20 Correct 1 ms 364 KB Output is correct
21 Correct 1 ms 364 KB Output is correct
22 Correct 1 ms 364 KB Output is correct
23 Correct 3 ms 620 KB Output is correct
24 Correct 3 ms 620 KB Output is correct
25 Correct 3 ms 620 KB Output is correct
26 Correct 6 ms 1004 KB Output is correct
27 Correct 7 ms 1004 KB Output is correct
28 Correct 5 ms 1132 KB Output is correct
29 Correct 5 ms 1004 KB Output is correct
30 Correct 5 ms 1004 KB Output is correct
31 Correct 6 ms 1388 KB Output is correct
32 Correct 29 ms 3820 KB Output is correct
33 Correct 29 ms 3820 KB Output is correct
34 Correct 34 ms 3820 KB Output is correct
35 Correct 222 ms 14212 KB Output is correct
36 Correct 228 ms 14060 KB Output is correct
37 Correct 224 ms 14060 KB Output is correct
38 Correct 141 ms 14432 KB Output is correct
39 Correct 146 ms 14416 KB Output is correct
40 Correct 154 ms 14292 KB Output is correct
41 Correct 196 ms 18016 KB Output is correct