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Submission #198266

# Submission time Handle Problem Language Result Execution time Memory
198266 2020-01-25T09:20:25 Z alishahali1382 Beads and wires (APIO14_beads) C++14
57 / 100
 263 ms 10104 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][0]=max(dp[node][0], 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

*/

Compilation message

beads.cpp: In function 'void dfs2(long long int, long long int)':
beads.cpp:58:6: warning: variable 'parw' set but not used [-Wunused-but-set-variable]
  int parw=0;
      ^~~~

Subtask #1
13.0 / 13.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 5084 KB Output is correct
2 Correct 6 ms 4984 KB Output is correct
3 Correct 7 ms 5116 KB Output is correct
4 Correct 8 ms 5112 KB Output is correct
5 Correct 6 ms 5172 KB Output is correct
6 Correct 7 ms 5116 KB Output is correct
7 Correct 7 ms 5112 KB Output is correct
8 Correct 6 ms 5112 KB Output is correct
9 Correct 6 ms 5112 KB Output is correct
10 Correct 3 ms 4984 KB Output is correct
11 Correct 6 ms 5112 KB Output is correct
12 Correct 6 ms 4984 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 5084 KB Output is correct
2 Correct 6 ms 4984 KB Output is correct
3 Correct 7 ms 5116 KB Output is correct
4 Correct 8 ms 5112 KB Output is correct
5 Correct 6 ms 5172 KB Output is correct
6 Correct 7 ms 5116 KB Output is correct
7 Correct 7 ms 5112 KB Output is correct
8 Correct 6 ms 5112 KB Output is correct
9 Correct 6 ms 5112 KB Output is correct
10 Correct 3 ms 4984 KB Output is correct
11 Correct 6 ms 5112 KB Output is correct
12 Correct 6 ms 4984 KB Output is correct
13 Correct 7 ms 4984 KB Output is correct
14 Correct 6 ms 5112 KB Output is correct
15 Correct 7 ms 5112 KB Output is correct
16 Correct 7 ms 5112 KB Output is correct
17 Correct 8 ms 5044 KB Output is correct
18 Correct 7 ms 5112 KB Output is correct
19 Correct 7 ms 5112 KB Output is correct
20 Correct 7 ms 5112 KB Output is correct
21 Correct 6 ms 5112 KB Output is correct
22 Correct 7 ms 5112 KB Output is correct

Subtask #3
29.0 / 29.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 5084 KB Output is correct
2 Correct 6 ms 4984 KB Output is correct
3 Correct 7 ms 5116 KB Output is correct
4 Correct 8 ms 5112 KB Output is correct
5 Correct 6 ms 5172 KB Output is correct
6 Correct 7 ms 5116 KB Output is correct
7 Correct 7 ms 5112 KB Output is correct
8 Correct 6 ms 5112 KB Output is correct
9 Correct 6 ms 5112 KB Output is correct
10 Correct 3 ms 4984 KB Output is correct
11 Correct 6 ms 5112 KB Output is correct
12 Correct 6 ms 4984 KB Output is correct
13 Correct 7 ms 4984 KB Output is correct
14 Correct 6 ms 5112 KB Output is correct
15 Correct 7 ms 5112 KB Output is correct
16 Correct 7 ms 5112 KB Output is correct
17 Correct 8 ms 5044 KB Output is correct
18 Correct 7 ms 5112 KB Output is correct
19 Correct 7 ms 5112 KB Output is correct
20 Correct 7 ms 5112 KB Output is correct
21 Correct 6 ms 5112 KB Output is correct
22 Correct 7 ms 5112 KB Output is correct
23 Correct 10 ms 5624 KB Output is correct
24 Correct 10 ms 5628 KB Output is correct
25 Correct 10 ms 5624 KB Output is correct
26 Correct 14 ms 6264 KB Output is correct
27 Correct 10 ms 6392 KB Output is correct
28 Correct 263 ms 6260 KB Output is correct
29 Correct 109 ms 6264 KB Output is correct
30 Correct 89 ms 6288 KB Output is correct
31 Correct 60 ms 6776 KB Output is correct

Subtask #4
0 / 43.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 5084 KB Output is correct
2 Correct 6 ms 4984 KB Output is correct
3 Correct 7 ms 5116 KB Output is correct
4 Correct 8 ms 5112 KB Output is correct
5 Correct 6 ms 5172 KB Output is correct
6 Correct 7 ms 5116 KB Output is correct
7 Correct 7 ms 5112 KB Output is correct
8 Correct 6 ms 5112 KB Output is correct
9 Correct 6 ms 5112 KB Output is correct
10 Correct 3 ms 4984 KB Output is correct
11 Correct 6 ms 5112 KB Output is correct
12 Correct 6 ms 4984 KB Output is correct
13 Correct 7 ms 4984 KB Output is correct
14 Correct 6 ms 5112 KB Output is correct
15 Correct 7 ms 5112 KB Output is correct
16 Correct 7 ms 5112 KB Output is correct
17 Correct 8 ms 5044 KB Output is correct
18 Correct 7 ms 5112 KB Output is correct
19 Correct 7 ms 5112 KB Output is correct
20 Correct 7 ms 5112 KB Output is correct
21 Correct 6 ms 5112 KB Output is correct
22 Correct 7 ms 5112 KB Output is correct
23 Correct 10 ms 5624 KB Output is correct
24 Correct 10 ms 5628 KB Output is correct
25 Correct 10 ms 5624 KB Output is correct
26 Correct 14 ms 6264 KB Output is correct
27 Correct 10 ms 6392 KB Output is correct
28 Correct 263 ms 6260 KB Output is correct
29 Correct 109 ms 6264 KB Output is correct
30 Correct 89 ms 6288 KB Output is correct
31 Correct 60 ms 6776 KB Output is correct
32 Runtime error 15 ms 10104 KB Execution killed with signal 11 (could be triggered by violating memory limits)
33 Halted 0 ms 0 KB -