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Submission #439313

# Submission time Handle Problem Language Result Execution time Memory
439313 2021-06-29T14:43:56 Z keta_tsimakuridze Beads and wires (APIO14_beads) C++14
100 / 100
 258 ms 23096 KB 
#include<bits/stdc++.h>
#define f first
#define s second
using namespace std;
const int N=2e5+5,mod=1e9+7,Inf=1e10;
int dp[N][2],n,x[N],leaf[N],ans;
vector<pair<int,int> > V[N];
pair<int,int> mx[N];
void dfs2(int u,int p) {
	ans = max(ans,dp[u][1]); 
	for(int i=0;i<V[u].size();i++) {
		int v = V[u][i].f;
		if(v==p) continue;
		
		int x = 0,bef0 = dp[u][0],bef1 = dp[u][1];
		if(!leaf[v]) x = max(dp[v][0] + V[u][i].s,dp[v][1]);
		dp[u][1] -= x;
		
		dp[u][0] = mx[u].f;
		if(mx[u].f == -x+dp[v][1]+V[u][i].s) dp[u][0] = mx[u].s;
		dp[u][0] += dp[u][1];
		x = max(dp[u][1],dp[u][0] + V[u][i].s);
		dp[v][1] += max(dp[u][1],dp[u][0] + V[u][i].s);
		dp[v][0] = max(dp[v][0],-x + V[u][i].s + dp[u][1]);
		if(-x +dp[u][1]+V[u][i].s > mx[v].f) {
			swap(mx[v].f,mx[v].s);
			mx[v].f = -x +dp[u][1]+V[u][i].s;
		}
		else mx[v].s = max(mx[v].s,-x +dp[u][1]+V[u][i].s);
		dfs2(v,u);
		dp[u][0] = bef0;
		dp[u][1] = bef1;
		
	}
}
void dfs(int u,int p) {
	leaf[u] = 0;
	dp[u][0] = dp[u][1]  = 0;
	dp[u][0] = -Inf;
	mx[u] = {-Inf,-Inf};
	for(int i=0;i<V[u].size();i++) {
		int v = V[u][i].f;
		if(v==p) continue;
		dfs(v,u);
		int x = 0;
		if(!leaf[v]) dp[u][1] += max(dp[v][1],dp[v][0] + V[u][i].s),x = max(dp[v][1],dp[v][0] + V[u][i].s);
		dp[u][0] = max(dp[u][0], -x +dp[v][1]+V[u][i].s);
		if(-x +dp[v][1]+V[u][i].s > mx[u].f) {
			swap(mx[u].f,mx[u].s);
			mx[u].f = -x +dp[v][1]+V[u][i].s;
		}
		else mx[u].s = max(mx[u].s,-x +dp[v][1]+V[u][i].s);
	}
	dp[u][0] += dp[u][1];

	if(V[u].size()==1 && p) leaf[u] = 1;
}
 main(){
   ios_base::sync_with_stdio(false),cin.tie(0),cout.tie(0);
	cin>>n;
	for(int i=2;i<=n;i++){
		int u,v,w;
		cin>>u>>v>>w;
		V[u].push_back({v,w});
		V[v].push_back({u,w});
	}
	int u = 1;
	for(int i=1;i<=n;i++) if(V[i].size()!=1){
		u = i; break;
	}
	dfs(u,0);
	//
	dfs2(u,0); 
	cout<<ans;
}

Compilation message

beads.cpp:5:33: warning: overflow in conversion from 'double' to 'int' changes value from '1.0e+10' to '2147483647' [-Woverflow]
    5 | const int N=2e5+5,mod=1e9+7,Inf=1e10;
      |                                 ^~~~
beads.cpp: In function 'void dfs2(int, int)':
beads.cpp:11:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   11 |  for(int i=0;i<V[u].size();i++) {
      |              ~^~~~~~~~~~~~
beads.cpp: In function 'void dfs(int, int)':
beads.cpp:41:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   41 |  for(int i=0;i<V[u].size();i++) {
      |              ~^~~~~~~~~~~~
beads.cpp: At global scope:
beads.cpp:58:2: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   58 |  main(){
      |  ^~~~

Subtask #1
13.0 / 13.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 4940 KB Output is correct
2 Correct 3 ms 4940 KB Output is correct
3 Correct 3 ms 4940 KB Output is correct
4 Correct 4 ms 5020 KB Output is correct
5 Correct 3 ms 4940 KB Output is correct
6 Correct 3 ms 4940 KB Output is correct
7 Correct 3 ms 4940 KB Output is correct
8 Correct 4 ms 4940 KB Output is correct
9 Correct 3 ms 4940 KB Output is correct
10 Correct 3 ms 4940 KB Output is correct
11 Correct 3 ms 4940 KB Output is correct
12 Correct 3 ms 4940 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 4940 KB Output is correct
2 Correct 3 ms 4940 KB Output is correct
3 Correct 3 ms 4940 KB Output is correct
4 Correct 4 ms 5020 KB Output is correct
5 Correct 3 ms 4940 KB Output is correct
6 Correct 3 ms 4940 KB Output is correct
7 Correct 3 ms 4940 KB Output is correct
8 Correct 4 ms 4940 KB Output is correct
9 Correct 3 ms 4940 KB Output is correct
10 Correct 3 ms 4940 KB Output is correct
11 Correct 3 ms 4940 KB Output is correct
12 Correct 3 ms 4940 KB Output is correct
13 Correct 3 ms 4940 KB Output is correct
14 Correct 3 ms 4940 KB Output is correct
15 Correct 4 ms 4940 KB Output is correct
16 Correct 4 ms 4940 KB Output is correct
17 Correct 4 ms 4940 KB Output is correct
18 Correct 3 ms 4940 KB Output is correct
19 Correct 3 ms 5008 KB Output is correct
20 Correct 3 ms 4940 KB Output is correct
21 Correct 3 ms 4940 KB Output is correct
22 Correct 4 ms 4940 KB Output is correct

Subtask #3
29.0 / 29.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 4940 KB Output is correct
2 Correct 3 ms 4940 KB Output is correct
3 Correct 3 ms 4940 KB Output is correct
4 Correct 4 ms 5020 KB Output is correct
5 Correct 3 ms 4940 KB Output is correct
6 Correct 3 ms 4940 KB Output is correct
7 Correct 3 ms 4940 KB Output is correct
8 Correct 4 ms 4940 KB Output is correct
9 Correct 3 ms 4940 KB Output is correct
10 Correct 3 ms 4940 KB Output is correct
11 Correct 3 ms 4940 KB Output is correct
12 Correct 3 ms 4940 KB Output is correct
13 Correct 3 ms 4940 KB Output is correct
14 Correct 3 ms 4940 KB Output is correct
15 Correct 4 ms 4940 KB Output is correct
16 Correct 4 ms 4940 KB Output is correct
17 Correct 4 ms 4940 KB Output is correct
18 Correct 3 ms 4940 KB Output is correct
19 Correct 3 ms 5008 KB Output is correct
20 Correct 3 ms 4940 KB Output is correct
21 Correct 3 ms 4940 KB Output is correct
22 Correct 4 ms 4940 KB Output is correct
23 Correct 6 ms 5196 KB Output is correct
24 Correct 6 ms 5196 KB Output is correct
25 Correct 7 ms 5244 KB Output is correct
26 Correct 10 ms 5580 KB Output is correct
27 Correct 10 ms 5568 KB Output is correct
28 Correct 10 ms 5580 KB Output is correct
29 Correct 8 ms 5580 KB Output is correct
30 Correct 9 ms 5580 KB Output is correct
31 Correct 8 ms 5836 KB Output is correct

Subtask #4
43.0 / 43.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 4940 KB Output is correct
2 Correct 3 ms 4940 KB Output is correct
3 Correct 3 ms 4940 KB Output is correct
4 Correct 4 ms 5020 KB Output is correct
5 Correct 3 ms 4940 KB Output is correct
6 Correct 3 ms 4940 KB Output is correct
7 Correct 3 ms 4940 KB Output is correct
8 Correct 4 ms 4940 KB Output is correct
9 Correct 3 ms 4940 KB Output is correct
10 Correct 3 ms 4940 KB Output is correct
11 Correct 3 ms 4940 KB Output is correct
12 Correct 3 ms 4940 KB Output is correct
13 Correct 3 ms 4940 KB Output is correct
14 Correct 3 ms 4940 KB Output is correct
15 Correct 4 ms 4940 KB Output is correct
16 Correct 4 ms 4940 KB Output is correct
17 Correct 4 ms 4940 KB Output is correct
18 Correct 3 ms 4940 KB Output is correct
19 Correct 3 ms 5008 KB Output is correct
20 Correct 3 ms 4940 KB Output is correct
21 Correct 3 ms 4940 KB Output is correct
22 Correct 4 ms 4940 KB Output is correct
23 Correct 6 ms 5196 KB Output is correct
24 Correct 6 ms 5196 KB Output is correct
25 Correct 7 ms 5244 KB Output is correct
26 Correct 10 ms 5580 KB Output is correct
27 Correct 10 ms 5568 KB Output is correct
28 Correct 10 ms 5580 KB Output is correct
29 Correct 8 ms 5580 KB Output is correct
30 Correct 9 ms 5580 KB Output is correct
31 Correct 8 ms 5836 KB Output is correct
32 Correct 33 ms 8452 KB Output is correct
33 Correct 42 ms 8616 KB Output is correct
34 Correct 34 ms 8616 KB Output is correct
35 Correct 258 ms 19892 KB Output is correct
36 Correct 221 ms 19896 KB Output is correct
37 Correct 232 ms 19896 KB Output is correct
38 Correct 164 ms 20272 KB Output is correct
39 Correct 143 ms 20260 KB Output is correct
40 Correct 166 ms 20232 KB Output is correct
41 Correct 246 ms 23096 KB Output is correct