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Submission #162290

# Submission time Handle Problem Language Result Execution time Memory
162290 2019-11-07T13:24:51 Z amoo_safar Beads and wires (APIO14_beads) C++14
28 / 100
 1000 ms 11792 KB 
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>

#define pb push_back
#define F first
#define S second
#define all(x) x.begin(), x.end()
#define debug(x) cerr << #x << " : " << x << '\n'

using namespace std;
using namespace __gnu_pbds;

typedef long long ll;
typedef long double ld;
typedef string str;
typedef pair<ll, ll> pll;
typedef pair<pll, pll> node;
typedef tree<ll, null_type, less<ll>, rb_tree_tag, tree_order_statistics_node_update> ordered_set;

const ll Mod = 1000000007LL;
const int Maxn = 2e5 + 10;
const int Maxk = 60;
const ll Inf = 2242545357980376863LL;
const ll Log = 30;

vector<pll> G[Maxn];

ll dp1[Maxn], dp2[Maxn];

ll DFS(ll u, ll p){
	ll adj;
	ll mx = -Inf;
	for(auto ed : G[u]){
		adj = ed.F;
		if(adj == p) continue;
		DFS(adj, u);
		dp1[u] += max(dp1[adj], dp2[adj] + ed.S);
		mx = max(mx, ed.S + dp1[adj] - max(dp1[adj], dp2[adj] + ed.S));
	}
	dp2[u] = dp1[u] + mx;
}

ll dpu1[Maxn], dpu2[Maxn];
ll pssm[Maxn], psmx[Maxn];
ll sfsm[Maxn], sfmx[Maxn];
ll ans = 0;
ll dfs(ll u, ll p, ll w){
	vector< pair<pll, pll> > S;
	ll adj;
	for(auto ed : G[u]){
		adj = ed.F;
		if(adj == p){
			S.pb({{dpu1[u], dpu2[u]}, {w, adj}});
		} else {
			S.pb({{dp1[adj], dp2[adj]}, {ed.S, adj}});
		}
	}
	ll N = S.size();
	
	pssm[0] = 0;
	for(int i = 1; i <= N; i++) pssm[i] = pssm[i - 1] + max(S[i - 1].F.F, S[i - 1].F.S + S[i - 1].S.F);
	psmx[0] = -Inf;
	for(int i = 1; i <= N; i++) psmx[i] = max(psmx[i - 1] , S[i - 1].F.F + S[i - 1].S.F - max(S[i - 1].F.F, S[i - 1].F.S + S[i - 1].S.F) );
	reverse(all(S));
	swap(pssm, sfsm);
	swap(psmx, sfmx);
	
	pssm[0] = 0;
	for(int i = 1; i <= N; i++) pssm[i] = pssm[i - 1] + max(S[i - 1].F.F, S[i - 1].F.S + S[i - 1].S.F);
	psmx[0] = -Inf;
	for(int i = 1; i <= N; i++) psmx[i] = max(psmx[i - 1] , S[i - 1].F.F + S[i - 1].S.F - max(S[i - 1].F.F, S[i - 1].F.S + S[i - 1].S.F) );
	//if(u == 3) cerr << 
	ans = max(pssm[N], ans);
	
	for(int i = 0; i < N; i++){
		adj = S[i].S.S;
		if(adj == p) continue;
		dpu1[adj] = pssm[i] + sfsm[N - 1 - i];
		dpu2[adj] = dpu1[adj] + max(psmx[i], sfmx[N - 1 - i]);
	}
	
	for(auto ed : G[u]){
		adj = ed.F;
		if(adj != p) dfs(adj, u, ed.S);
	}
}


int main(){
	ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
	ll n;
	cin >> n;
	ll u, v, w;
	for(int i = 1; i < n; i++){
		cin >> u >> v >> w;
		G[u].pb({v, w});
		G[v].pb({u, w});
	}
	DFS(1, -1);
	dfs(1, -1, 0);
	cout << ans;
	return 0;
}
/*
5
1 2 10
1 3 40
1 4 15
1 5 20

*/

Compilation message

beads.cpp: In function 'll DFS(ll, ll)':
beads.cpp:41:1: warning: no return statement in function returning non-void [-Wreturn-type]
 }
 ^
beads.cpp: In function 'll dfs(ll, ll, ll)':
beads.cpp:86:1: warning: no return statement in function returning non-void [-Wreturn-type]
 }
 ^

Subtask #1
13.0 / 13.0

# Verdict Execution time Memory Grader output
1 Correct 16 ms 11384 KB Output is correct
2 Correct 19 ms 11256 KB Output is correct
3 Correct 19 ms 11384 KB Output is correct
4 Correct 21 ms 11356 KB Output is correct
5 Correct 19 ms 11384 KB Output is correct
6 Correct 20 ms 11384 KB Output is correct
7 Correct 19 ms 11384 KB Output is correct
8 Correct 19 ms 11256 KB Output is correct
9 Correct 20 ms 11472 KB Output is correct
10 Correct 19 ms 11512 KB Output is correct
11 Correct 19 ms 11384 KB Output is correct
12 Correct 19 ms 11384 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 16 ms 11384 KB Output is correct
2 Correct 19 ms 11256 KB Output is correct
3 Correct 19 ms 11384 KB Output is correct
4 Correct 21 ms 11356 KB Output is correct
5 Correct 19 ms 11384 KB Output is correct
6 Correct 20 ms 11384 KB Output is correct
7 Correct 19 ms 11384 KB Output is correct
8 Correct 19 ms 11256 KB Output is correct
9 Correct 20 ms 11472 KB Output is correct
10 Correct 19 ms 11512 KB Output is correct
11 Correct 19 ms 11384 KB Output is correct
12 Correct 19 ms 11384 KB Output is correct
13 Correct 65 ms 11384 KB Output is correct
14 Correct 62 ms 11372 KB Output is correct
15 Correct 63 ms 11300 KB Output is correct
16 Correct 110 ms 11384 KB Output is correct
17 Correct 112 ms 11484 KB Output is correct
18 Correct 117 ms 11484 KB Output is correct
19 Correct 112 ms 11400 KB Output is correct
20 Correct 108 ms 11384 KB Output is correct
21 Correct 110 ms 11512 KB Output is correct
22 Correct 116 ms 11388 KB Output is correct

Subtask #3
0 / 29.0

# Verdict Execution time Memory Grader output
1 Correct 16 ms 11384 KB Output is correct
2 Correct 19 ms 11256 KB Output is correct
3 Correct 19 ms 11384 KB Output is correct
4 Correct 21 ms 11356 KB Output is correct
5 Correct 19 ms 11384 KB Output is correct
6 Correct 20 ms 11384 KB Output is correct
7 Correct 19 ms 11384 KB Output is correct
8 Correct 19 ms 11256 KB Output is correct
9 Correct 20 ms 11472 KB Output is correct
10 Correct 19 ms 11512 KB Output is correct
11 Correct 19 ms 11384 KB Output is correct
12 Correct 19 ms 11384 KB Output is correct
13 Correct 65 ms 11384 KB Output is correct
14 Correct 62 ms 11372 KB Output is correct
15 Correct 63 ms 11300 KB Output is correct
16 Correct 110 ms 11384 KB Output is correct
17 Correct 112 ms 11484 KB Output is correct
18 Correct 117 ms 11484 KB Output is correct
19 Correct 112 ms 11400 KB Output is correct
20 Correct 108 ms 11384 KB Output is correct
21 Correct 110 ms 11512 KB Output is correct
22 Correct 116 ms 11388 KB Output is correct
23 Execution timed out 1065 ms 11792 KB Time limit exceeded
24 Halted 0 ms 0 KB -

Subtask #4
0 / 43.0

# Verdict Execution time Memory Grader output
1 Correct 16 ms 11384 KB Output is correct
2 Correct 19 ms 11256 KB Output is correct
3 Correct 19 ms 11384 KB Output is correct
4 Correct 21 ms 11356 KB Output is correct
5 Correct 19 ms 11384 KB Output is correct
6 Correct 20 ms 11384 KB Output is correct
7 Correct 19 ms 11384 KB Output is correct
8 Correct 19 ms 11256 KB Output is correct
9 Correct 20 ms 11472 KB Output is correct
10 Correct 19 ms 11512 KB Output is correct
11 Correct 19 ms 11384 KB Output is correct
12 Correct 19 ms 11384 KB Output is correct
13 Correct 65 ms 11384 KB Output is correct
14 Correct 62 ms 11372 KB Output is correct
15 Correct 63 ms 11300 KB Output is correct
16 Correct 110 ms 11384 KB Output is correct
17 Correct 112 ms 11484 KB Output is correct
18 Correct 117 ms 11484 KB Output is correct
19 Correct 112 ms 11400 KB Output is correct
20 Correct 108 ms 11384 KB Output is correct
21 Correct 110 ms 11512 KB Output is correct
22 Correct 116 ms 11388 KB Output is correct
23 Execution timed out 1065 ms 11792 KB Time limit exceeded
24 Halted 0 ms 0 KB -