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Submission #552194

# Submission time Handle Problem Language Result Execution time Memory
552194 2022-04-22T16:36:44 Z QwertyPi Beads and wires (APIO14_beads) C++14
100 / 100
 328 ms 42992 KB 
#include <bits/stdc++.h>
#define int long long
#define fi first
#define se second
#define pb push_back

using namespace std;
typedef pair<int, int> pii;
const int N = 2e5 + 5;
vector<pii> G[N];
int dp[N][4], W[N], p[N];

void dfs(int v, int par = -1){
	for(auto [i, w] : G[v]){
		if(i == par) continue;
		W[i] = w;
		dfs(i, v);
	}
	// Case 0: do nothing
	int am0 = 0, a0 = 0, a1 = 0;
	vector<int> tune1;
	for(auto [i, w] : G[v]){
		if(i != par) a0 += dp[i][2], a1 += dp[i][2], tune1.pb(dp[i][3] - dp[i][2]);
	}
	sort(tune1.begin(), tune1.end(), greater<>()); if(tune1.size()) a1 += tune1[0];
	dp[v][0] = a0, dp[v][1] = a1;
	// Case 1: p[v]-v-son[v]
	vector<pii> co2, co3;
	for(auto [i, w] : G[v]){
		if(i != par) co2.pb({w + dp[i][0] - dp[i][2], i}), co3.pb({w + dp[i][1] - dp[i][2], i});
	}
	sort(co2.begin(), co2.end(), greater<>());
	sort(co3.begin(), co3.end(), greater<>());
//	for(auto i : co2) cout << i << ' '; cout << endl;
//	for(auto i : co3) cout << i << ' '; cout << endl;
	if(par != -1){
		if(co2.size()) dp[v][2] = max(dp[v][2], a0 + co2[0].fi + W[v]);
		if(co3.size()) dp[v][3] = max(dp[v][3], a0 + co3[0].fi + W[v]);
	}
	// Case 2: son1[v]-v-son2[v]
	if(co2.size() >= 2) dp[v][1] = max(dp[v][1], a0 + (co2[0].se == co3[0].se ? max(co2[0].fi + co3[1].fi, co2[1].fi + co3[0].fi) : co2[0].fi + co3[0].fi));
	dp[v][2] = max(dp[v][0], dp[v][2]);
	dp[v][1] = max(dp[v][0], dp[v][1]);
	dp[v][3] = max(dp[v][1], dp[v][3]);
	dp[v][3] = max(dp[v][2], dp[v][3]);
}

int32_t main(){
	int n;
	cin >> n;
	for(int i = 0; i < n - 1; i++){
		int u, v, we;
		cin >> u >> v >> we;
		G[u].pb({v, we});
		G[v].pb({u, we});
	}
	dfs(1);
//	for(int i = 1; i <= n; i++){
//		cout << i << ": " << dp[i][0] << ' ' << dp[i][1] << ' ' << dp[i][2] << ' ' << dp[i][3] << endl;
//	}
	int ans = 0; for(int j = 0; j < 4; j++) ans = max(ans, dp[1][j]);
	cout << ans << endl;
}

Compilation message

beads.cpp: In function 'void dfs(long long int, long long int)':
beads.cpp:14:11: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   14 |  for(auto [i, w] : G[v]){
      |           ^
beads.cpp:22:11: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   22 |  for(auto [i, w] : G[v]){
      |           ^
beads.cpp:29:11: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   29 |  for(auto [i, w] : G[v]){
      |           ^
beads.cpp:20:6: warning: unused variable 'am0' [-Wunused-variable]
   20 |  int am0 = 0, a0 = 0, a1 = 0;
      |      ^~~

Subtask #1
13.0 / 13.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 4948 KB Output is correct
2 Correct 2 ms 4948 KB Output is correct
3 Correct 3 ms 4948 KB Output is correct
4 Correct 3 ms 4948 KB Output is correct
5 Correct 2 ms 4948 KB Output is correct
6 Correct 3 ms 4948 KB Output is correct
7 Correct 3 ms 5020 KB Output is correct
8 Correct 3 ms 4948 KB Output is correct
9 Correct 3 ms 4944 KB Output is correct
10 Correct 4 ms 4948 KB Output is correct
11 Correct 3 ms 4948 KB Output is correct
12 Correct 3 ms 4948 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 4948 KB Output is correct
2 Correct 2 ms 4948 KB Output is correct
3 Correct 3 ms 4948 KB Output is correct
4 Correct 3 ms 4948 KB Output is correct
5 Correct 2 ms 4948 KB Output is correct
6 Correct 3 ms 4948 KB Output is correct
7 Correct 3 ms 5020 KB Output is correct
8 Correct 3 ms 4948 KB Output is correct
9 Correct 3 ms 4944 KB Output is correct
10 Correct 4 ms 4948 KB Output is correct
11 Correct 3 ms 4948 KB Output is correct
12 Correct 3 ms 4948 KB Output is correct
13 Correct 3 ms 4948 KB Output is correct
14 Correct 3 ms 4948 KB Output is correct
15 Correct 3 ms 4948 KB Output is correct
16 Correct 4 ms 4948 KB Output is correct
17 Correct 3 ms 5004 KB Output is correct
18 Correct 3 ms 4948 KB Output is correct
19 Correct 3 ms 5004 KB Output is correct
20 Correct 3 ms 4948 KB Output is correct
21 Correct 3 ms 4948 KB Output is correct
22 Correct 3 ms 5000 KB Output is correct

Subtask #3
29.0 / 29.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 4948 KB Output is correct
2 Correct 2 ms 4948 KB Output is correct
3 Correct 3 ms 4948 KB Output is correct
4 Correct 3 ms 4948 KB Output is correct
5 Correct 2 ms 4948 KB Output is correct
6 Correct 3 ms 4948 KB Output is correct
7 Correct 3 ms 5020 KB Output is correct
8 Correct 3 ms 4948 KB Output is correct
9 Correct 3 ms 4944 KB Output is correct
10 Correct 4 ms 4948 KB Output is correct
11 Correct 3 ms 4948 KB Output is correct
12 Correct 3 ms 4948 KB Output is correct
13 Correct 3 ms 4948 KB Output is correct
14 Correct 3 ms 4948 KB Output is correct
15 Correct 3 ms 4948 KB Output is correct
16 Correct 4 ms 4948 KB Output is correct
17 Correct 3 ms 5004 KB Output is correct
18 Correct 3 ms 4948 KB Output is correct
19 Correct 3 ms 5004 KB Output is correct
20 Correct 3 ms 4948 KB Output is correct
21 Correct 3 ms 4948 KB Output is correct
22 Correct 3 ms 5000 KB Output is correct
23 Correct 8 ms 5460 KB Output is correct
24 Correct 8 ms 5524 KB Output is correct
25 Correct 8 ms 5460 KB Output is correct
26 Correct 16 ms 6040 KB Output is correct
27 Correct 14 ms 6060 KB Output is correct
28 Correct 13 ms 6676 KB Output is correct
29 Correct 14 ms 6224 KB Output is correct
30 Correct 13 ms 6192 KB Output is correct
31 Correct 14 ms 7192 KB Output is correct

Subtask #4
43.0 / 43.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 4948 KB Output is correct
2 Correct 2 ms 4948 KB Output is correct
3 Correct 3 ms 4948 KB Output is correct
4 Correct 3 ms 4948 KB Output is correct
5 Correct 2 ms 4948 KB Output is correct
6 Correct 3 ms 4948 KB Output is correct
7 Correct 3 ms 5020 KB Output is correct
8 Correct 3 ms 4948 KB Output is correct
9 Correct 3 ms 4944 KB Output is correct
10 Correct 4 ms 4948 KB Output is correct
11 Correct 3 ms 4948 KB Output is correct
12 Correct 3 ms 4948 KB Output is correct
13 Correct 3 ms 4948 KB Output is correct
14 Correct 3 ms 4948 KB Output is correct
15 Correct 3 ms 4948 KB Output is correct
16 Correct 4 ms 4948 KB Output is correct
17 Correct 3 ms 5004 KB Output is correct
18 Correct 3 ms 4948 KB Output is correct
19 Correct 3 ms 5004 KB Output is correct
20 Correct 3 ms 4948 KB Output is correct
21 Correct 3 ms 4948 KB Output is correct
22 Correct 3 ms 5000 KB Output is correct
23 Correct 8 ms 5460 KB Output is correct
24 Correct 8 ms 5524 KB Output is correct
25 Correct 8 ms 5460 KB Output is correct
26 Correct 16 ms 6040 KB Output is correct
27 Correct 14 ms 6060 KB Output is correct
28 Correct 13 ms 6676 KB Output is correct
29 Correct 14 ms 6224 KB Output is correct
30 Correct 13 ms 6192 KB Output is correct
31 Correct 14 ms 7192 KB Output is correct
32 Correct 60 ms 10188 KB Output is correct
33 Correct 67 ms 10208 KB Output is correct
34 Correct 63 ms 10188 KB Output is correct
35 Correct 286 ms 26660 KB Output is correct
36 Correct 328 ms 26588 KB Output is correct
37 Correct 277 ms 26684 KB Output is correct
38 Correct 276 ms 38592 KB Output is correct
39 Correct 258 ms 32628 KB Output is correct
40 Correct 270 ms 29924 KB Output is correct
41 Correct 318 ms 42992 KB Output is correct