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Submission #162352

# Submission time Handle Problem Language Result Execution time Memory
162352 2019-11-07T16:27:01 Z HungAnhGoldIBO2020 Beads and wires (APIO14_beads) C++14
100 / 100
 221 ms 24560 KB 
#include<bits/stdc++.h>
#define use 1
#define mid 2
#define nouse 0
#define nomid 0
using namespace std;
const int N=2e5+1;
const int inf=1e9+7;
int dp[4][N],val[N];
vector<pair<int,int> > adj[N];
void dfs(int x,int p){
	int mx_nouse_nomid1=-inf,mx_nouse_nomid2=-inf,mx_nouse_mid1=-inf,mx_nouse_mid2=-inf,mx_mid=-inf;
	int idx_nouse_nomid1=0,idx_nouse_nomid2=0,idx_nouse_mid1=0,idx_nouse_mid2=0;
	for(auto j:adj[x]){
		int i=j.first;
		if(i!=p){
			val[i]=j.second;
			dfs(i,x);
			int pts=max(dp[nouse|nomid][i],dp[use|nomid][i]);
			dp[nouse|nomid][x]+=pts;
			mx_mid=max(mx_mid,max(dp[nouse|mid][i],dp[use|mid][i])-pts);
			int pts_nouse_nomid=dp[nouse|nomid][i]+j.second-pts;
			if(pts_nouse_nomid>mx_nouse_nomid1){
				mx_nouse_nomid2=mx_nouse_nomid1;
				idx_nouse_nomid2=idx_nouse_nomid1;
				mx_nouse_nomid1=pts_nouse_nomid;
				idx_nouse_nomid1=i;
			}
			else{
				if(pts_nouse_nomid>mx_nouse_nomid2){
					mx_nouse_nomid2=pts_nouse_nomid;
					idx_nouse_nomid2=i;
				}
			}
			int pts_nouse_mid=dp[nouse|mid][i]+j.second-pts;
			if(pts_nouse_mid>mx_nouse_mid1){
				mx_nouse_mid2=mx_nouse_mid1;
				idx_nouse_mid2=idx_nouse_mid1;
				mx_nouse_mid1=pts_nouse_mid;
				idx_nouse_mid1=i;
			}
			else{
				if(pts_nouse_mid>mx_nouse_mid2){
					mx_nouse_mid2=pts_nouse_mid;
					idx_nouse_mid2=i;
				}
			}
		}
	}
	dp[use|nomid][x]=dp[nouse|nomid][x]+mx_nouse_nomid1+val[x];
	dp[use|mid][x]=dp[nouse|nomid][x]+mx_nouse_mid1+val[x];
	dp[nouse|mid][x]=dp[nouse|nomid][x]+max(mx_mid,0);
	dp[nouse|mid][x]=max(dp[nouse|mid][x],dp[nouse|nomid][x]+mx_nouse_nomid1+mx_nouse_nomid2);
	if(idx_nouse_mid1!=idx_nouse_nomid1){
		dp[nouse|mid][x]=max(dp[nouse|mid][x],dp[nouse|nomid][x]+mx_nouse_mid1+mx_nouse_nomid1);
	}
	else{
		dp[nouse|mid][x]=max(dp[nouse|mid][x],dp[nouse|nomid][x]+mx_nouse_mid1+mx_nouse_nomid2);
		dp[nouse|mid][x]=max(dp[nouse|mid][x],dp[nouse|nomid][x]+mx_nouse_mid2+mx_nouse_nomid1);
	}
}
signed main(){
	ios::sync_with_stdio(0);
	cin.tie(0);
	int n,i,j,k,l;
	cin>>n;
	for(i=1;i<n;i++){
		cin>>j>>k>>l;
		adj[j].push_back({k,l});
		adj[k].push_back({j,l});
	}
	dfs(1,1);
	cout<<max(dp[nouse|mid][1],dp[nouse|nomid][1]);
}
/*
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 dfs(int, int)':
beads.cpp:13:25: warning: variable 'idx_nouse_nomid2' set but not used [-Wunused-but-set-variable]
  int idx_nouse_nomid1=0,idx_nouse_nomid2=0,idx_nouse_mid1=0,idx_nouse_mid2=0;
                         ^~~~~~~~~~~~~~~~
beads.cpp:13:61: warning: variable 'idx_nouse_mid2' set but not used [-Wunused-but-set-variable]
  int idx_nouse_nomid1=0,idx_nouse_nomid2=0,idx_nouse_mid1=0,idx_nouse_mid2=0;
                                                             ^~~~~~~~~~~~~~

Subtask #1
13.0 / 13.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 5112 KB Output is correct
2 Correct 10 ms 5112 KB Output is correct
3 Correct 6 ms 4984 KB Output is correct
4 Correct 6 ms 5112 KB Output is correct
5 Correct 6 ms 4984 KB Output is correct
6 Correct 7 ms 5112 KB Output is correct
7 Correct 6 ms 4984 KB Output is correct
8 Correct 6 ms 5112 KB Output is correct
9 Correct 6 ms 4984 KB Output is correct
10 Correct 6 ms 5112 KB Output is correct
11 Correct 6 ms 5112 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 6 ms 5112 KB Output is correct
2 Correct 10 ms 5112 KB Output is correct
3 Correct 6 ms 4984 KB Output is correct
4 Correct 6 ms 5112 KB Output is correct
5 Correct 6 ms 4984 KB Output is correct
6 Correct 7 ms 5112 KB Output is correct
7 Correct 6 ms 4984 KB Output is correct
8 Correct 6 ms 5112 KB Output is correct
9 Correct 6 ms 4984 KB Output is correct
10 Correct 6 ms 5112 KB Output is correct
11 Correct 6 ms 5112 KB Output is correct
12 Correct 6 ms 5112 KB Output is correct
13 Correct 6 ms 4984 KB Output is correct
14 Correct 6 ms 5112 KB Output is correct
15 Correct 7 ms 4984 KB Output is correct
16 Correct 6 ms 5240 KB Output is correct
17 Correct 7 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 4988 KB Output is correct
21 Correct 6 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 6 ms 5112 KB Output is correct
2 Correct 10 ms 5112 KB Output is correct
3 Correct 6 ms 4984 KB Output is correct
4 Correct 6 ms 5112 KB Output is correct
5 Correct 6 ms 4984 KB Output is correct
6 Correct 7 ms 5112 KB Output is correct
7 Correct 6 ms 4984 KB Output is correct
8 Correct 6 ms 5112 KB Output is correct
9 Correct 6 ms 4984 KB Output is correct
10 Correct 6 ms 5112 KB Output is correct
11 Correct 6 ms 5112 KB Output is correct
12 Correct 6 ms 5112 KB Output is correct
13 Correct 6 ms 4984 KB Output is correct
14 Correct 6 ms 5112 KB Output is correct
15 Correct 7 ms 4984 KB Output is correct
16 Correct 6 ms 5240 KB Output is correct
17 Correct 7 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 4988 KB Output is correct
21 Correct 6 ms 5112 KB Output is correct
22 Correct 6 ms 5112 KB Output is correct
23 Correct 9 ms 5368 KB Output is correct
24 Correct 9 ms 5368 KB Output is correct
25 Correct 10 ms 5368 KB Output is correct
26 Correct 13 ms 5752 KB Output is correct
27 Correct 16 ms 5752 KB Output is correct
28 Correct 11 ms 5880 KB Output is correct
29 Correct 11 ms 5752 KB Output is correct
30 Correct 11 ms 5880 KB Output is correct
31 Correct 12 ms 6268 KB Output is correct

Subtask #4
43.0 / 43.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 5112 KB Output is correct
2 Correct 10 ms 5112 KB Output is correct
3 Correct 6 ms 4984 KB Output is correct
4 Correct 6 ms 5112 KB Output is correct
5 Correct 6 ms 4984 KB Output is correct
6 Correct 7 ms 5112 KB Output is correct
7 Correct 6 ms 4984 KB Output is correct
8 Correct 6 ms 5112 KB Output is correct
9 Correct 6 ms 4984 KB Output is correct
10 Correct 6 ms 5112 KB Output is correct
11 Correct 6 ms 5112 KB Output is correct
12 Correct 6 ms 5112 KB Output is correct
13 Correct 6 ms 4984 KB Output is correct
14 Correct 6 ms 5112 KB Output is correct
15 Correct 7 ms 4984 KB Output is correct
16 Correct 6 ms 5240 KB Output is correct
17 Correct 7 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 4988 KB Output is correct
21 Correct 6 ms 5112 KB Output is correct
22 Correct 6 ms 5112 KB Output is correct
23 Correct 9 ms 5368 KB Output is correct
24 Correct 9 ms 5368 KB Output is correct
25 Correct 10 ms 5368 KB Output is correct
26 Correct 13 ms 5752 KB Output is correct
27 Correct 16 ms 5752 KB Output is correct
28 Correct 11 ms 5880 KB Output is correct
29 Correct 11 ms 5752 KB Output is correct
30 Correct 11 ms 5880 KB Output is correct
31 Correct 12 ms 6268 KB Output is correct
32 Correct 40 ms 8692 KB Output is correct
33 Correct 42 ms 8712 KB Output is correct
34 Correct 39 ms 8616 KB Output is correct
35 Correct 216 ms 19932 KB Output is correct
36 Correct 221 ms 19948 KB Output is correct
37 Correct 219 ms 20008 KB Output is correct
38 Correct 158 ms 20432 KB Output is correct
39 Correct 164 ms 19696 KB Output is correct
40 Correct 165 ms 20324 KB Output is correct
41 Correct 194 ms 24560 KB Output is correct