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Submission #198268

# Submission time Handle Problem Language Result Execution time Memory
198268 2020-01-25T09:22:39 Z alishahali1382 Beads and wires (APIO14_beads) C++14
100 / 100
 286 ms 36476 KB 
#include <bits/stdc++.h>
#pragma GCC optimize ("O2")
#pragma GCC optimize ("unroll-loops")
//#pragma GCC optimize("no-stack-protector,fast-math")

#define int long long

using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<pii, int> piii;
typedef pair<ll, ll> pll;
#define debug(x) cerr<<#x<<'='<<(x)<<endl;
#define debugp(x) cerr<<#x<<"= {"<<(x.first)<<", "<<(x.second)<<"}"<<endl;
#define debug2(x, y) cerr<<"{"<<#x<<", "<<#y<<"} = {"<<(x)<<", "<<(y)<<"}"<<endl;
#define debugv(v) cerr<<#v<<" : ";for (auto x:v) cerr<<x<<' ';cerr<<endl;
#define all(x) x.begin(), x.end()
#define pb push_back
#define kill(x) return cout<<x<<'\n', 0;

const ld eps=1e-7;
const int inf=2000000010;
const ll INF=10000000000000010LL;
const int mod = 1000000007;
const int MAXN = 200010, LOG=20;

int n, m, k, u, v, x, y, t, a, b, ans;
int dp[MAXN][2];
int sum[MAXN];
//int dp2[MAXN][2];
pii mx[MAXN][2];
vector<pii> G[MAXN];

void dfs1(int node, int par){
	dp[node][0]=0;
	dp[node][1]=-inf;
	for (pii p:G[node]) if (p.first!=par) dfs1(p.first, node);
	
	sum[node]=0;
	for (pii p:G[node]) if (p.first!=par) sum[node]+=max(dp[p.first][0], dp[p.first][1]+p.second);
	dp[node][0]=sum[node];
	
	mx[node][0]=mx[node][1]={-inf, 0};
	for (pii p:G[node]) if (p.first!=par){
		pii tmp={min(p.second, dp[p.first][0]-dp[p.first][1]), p.first};
		if (tmp>mx[node][1]) mx[node][1]=tmp;
		if (mx[node][1]>mx[node][0]) swap(mx[node][0], mx[node][1]);
	}
	dp[node][1]=sum[node]+mx[node][0].first;
	
	//dp[node][0]=sum;
	
}

void dfs2(int node, int par){
	ans=max(ans, dp[node][0]);
	int parw=0;
	for (pii p:G[node]) if (p.first==par) parw=p.second;
	
	for (pii p:G[node]) if (p.first!=par){
		int v=p.first, w=p.second;
		int nd0=dp[node][0], nd1=dp[node][1], ns=sum[node];
		int vd0=dp[v][0], vd1=dp[v][1], vs=sum[v];
		
		sum[node]-=max(dp[v][0], dp[v][1]+w);
		dp[node][0]=sum[node];
		dp[node][1]=-inf;
		
		dp[node][1]=sum[node]+mx[node][0].first;
		if (v==mx[node][0].second) dp[node][1]=sum[node]+mx[node][1].first;
		if (node!=1) dp[node][1]=max(dp[node][1], sum[node]+min(parw, dp[par][0]-dp[par][1]));
		
		//for (pii pp:G[node]) if (/*pp.first!=par && */pp.first!=v) dp[node][1]=max(dp[node][1], sum[node]+min(pp.second, dp[pp.first][0]-dp[pp.first][1]));
		
		sum[v]+=max(dp[node][0], dp[node][1]+w);
		dp[v][0]=sum[v];
		dp[v][1]=max(sum[v]+mx[v][0].first, sum[v]+min(w, dp[node][0]-dp[node][1]));
		
		dfs2(v, node);
		
		dp[node][0]=nd0;
		dp[node][1]=nd1;
		sum[node]=ns;
		dp[v][0]=vd0;
		dp[v][1]=vd1;
		sum[v]=vs;
	}
}

int32_t main(){
	ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
	//freopen("input.txt", "r", stdin);
	//freopen("output.txt", "w", stdout);
	cin>>n;
	//assert(n<=10000);
	for (int i=1; i<n; i++){
		cin>>u>>v>>x;
		G[u].pb({v, x});
		G[v].pb({u, x});
	}
	
	/*
	for (int i=1; i<=n; i++){
		for (int j=1; j<=n; j++) dp[j][0]=0, dp[j][1]=-inf, sum[j]=0;
		dfs1(i, i);
		ans=max(ans, dp[i][0]);
		//debug2(i, dp[i][0])
	}*/
	
	dfs1(1, 1);
	dfs2(1, 1);
	
	cout<<ans<<'\n';
	
	return 0;
}
/*
5
1 2 10
1 3 40
1 4 15
1 5 20


10
4 10 2
1 2 21
1 3 13
6 7 1
7 9 5
2 4 3
2 5 8
1 6 55
6 8 34

*/

Subtask #1
13.0 / 13.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 5112 KB Output is correct
2 Correct 6 ms 4984 KB Output is correct
3 Correct 10 ms 5112 KB Output is correct
4 Correct 5 ms 5240 KB Output is correct
5 Correct 6 ms 4984 KB Output is correct
6 Correct 6 ms 4984 KB Output is correct
7 Correct 6 ms 4984 KB Output is correct
8 Correct 6 ms 4984 KB Output is correct
9 Correct 6 ms 5112 KB Output is correct
10 Correct 6 ms 4984 KB Output is correct
11 Correct 6 ms 4984 KB Output is correct
12 Correct 6 ms 5112 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 5112 KB Output is correct
2 Correct 6 ms 4984 KB Output is correct
3 Correct 10 ms 5112 KB Output is correct
4 Correct 5 ms 5240 KB Output is correct
5 Correct 6 ms 4984 KB Output is correct
6 Correct 6 ms 4984 KB Output is correct
7 Correct 6 ms 4984 KB Output is correct
8 Correct 6 ms 4984 KB Output is correct
9 Correct 6 ms 5112 KB Output is correct
10 Correct 6 ms 4984 KB Output is correct
11 Correct 6 ms 4984 KB Output is correct
12 Correct 6 ms 5112 KB Output is correct
13 Correct 6 ms 5112 KB Output is correct
14 Correct 6 ms 4988 KB Output is correct
15 Correct 6 ms 4984 KB Output is correct
16 Correct 7 ms 5156 KB Output is correct
17 Correct 6 ms 5112 KB Output is correct
18 Correct 6 ms 5112 KB Output is correct
19 Correct 6 ms 5112 KB Output is correct
20 Correct 6 ms 5112 KB Output is correct
21 Correct 12 ms 5112 KB Output is correct
22 Correct 6 ms 5112 KB Output is correct

Subtask #3
29.0 / 29.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 5112 KB Output is correct
2 Correct 6 ms 4984 KB Output is correct
3 Correct 10 ms 5112 KB Output is correct
4 Correct 5 ms 5240 KB Output is correct
5 Correct 6 ms 4984 KB Output is correct
6 Correct 6 ms 4984 KB Output is correct
7 Correct 6 ms 4984 KB Output is correct
8 Correct 6 ms 4984 KB Output is correct
9 Correct 6 ms 5112 KB Output is correct
10 Correct 6 ms 4984 KB Output is correct
11 Correct 6 ms 4984 KB Output is correct
12 Correct 6 ms 5112 KB Output is correct
13 Correct 6 ms 5112 KB Output is correct
14 Correct 6 ms 4988 KB Output is correct
15 Correct 6 ms 4984 KB Output is correct
16 Correct 7 ms 5156 KB Output is correct
17 Correct 6 ms 5112 KB Output is correct
18 Correct 6 ms 5112 KB Output is correct
19 Correct 6 ms 5112 KB Output is correct
20 Correct 6 ms 5112 KB Output is correct
21 Correct 12 ms 5112 KB Output is correct
22 Correct 6 ms 5112 KB Output is correct
23 Correct 11 ms 5624 KB Output is correct
24 Correct 10 ms 5624 KB Output is correct
25 Correct 10 ms 5752 KB Output is correct
26 Correct 14 ms 6264 KB Output is correct
27 Correct 14 ms 6140 KB Output is correct
28 Correct 12 ms 6132 KB Output is correct
29 Correct 12 ms 6008 KB Output is correct
30 Correct 13 ms 6136 KB Output is correct
31 Correct 14 ms 6648 KB Output is correct

Subtask #4
43.0 / 43.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 5112 KB Output is correct
2 Correct 6 ms 4984 KB Output is correct
3 Correct 10 ms 5112 KB Output is correct
4 Correct 5 ms 5240 KB Output is correct
5 Correct 6 ms 4984 KB Output is correct
6 Correct 6 ms 4984 KB Output is correct
7 Correct 6 ms 4984 KB Output is correct
8 Correct 6 ms 4984 KB Output is correct
9 Correct 6 ms 5112 KB Output is correct
10 Correct 6 ms 4984 KB Output is correct
11 Correct 6 ms 4984 KB Output is correct
12 Correct 6 ms 5112 KB Output is correct
13 Correct 6 ms 5112 KB Output is correct
14 Correct 6 ms 4988 KB Output is correct
15 Correct 6 ms 4984 KB Output is correct
16 Correct 7 ms 5156 KB Output is correct
17 Correct 6 ms 5112 KB Output is correct
18 Correct 6 ms 5112 KB Output is correct
19 Correct 6 ms 5112 KB Output is correct
20 Correct 6 ms 5112 KB Output is correct
21 Correct 12 ms 5112 KB Output is correct
22 Correct 6 ms 5112 KB Output is correct
23 Correct 11 ms 5624 KB Output is correct
24 Correct 10 ms 5624 KB Output is correct
25 Correct 10 ms 5752 KB Output is correct
26 Correct 14 ms 6264 KB Output is correct
27 Correct 14 ms 6140 KB Output is correct
28 Correct 12 ms 6132 KB Output is correct
29 Correct 12 ms 6008 KB Output is correct
30 Correct 13 ms 6136 KB Output is correct
31 Correct 14 ms 6648 KB Output is correct
32 Correct 51 ms 10412 KB Output is correct
33 Correct 61 ms 10412 KB Output is correct
34 Correct 50 ms 10412 KB Output is correct
35 Correct 282 ms 26296 KB Output is correct
36 Correct 283 ms 26360 KB Output is correct
37 Correct 286 ms 26336 KB Output is correct
38 Correct 198 ms 25436 KB Output is correct
39 Correct 209 ms 29008 KB Output is correct
40 Correct 197 ms 28964 KB Output is correct
41 Correct 278 ms 36476 KB Output is correct