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Submission #198239

# Submission time Handle Problem Language Result Execution time Memory
198239 2020-01-25T08:21:39 Z mehrdad_sohrabi Beads and wires (APIO14_beads) C++14
100 / 100
 275 ms 23448 KB 
#include <bits/stdc++.h>
typedef int ll;
typedef long double ld;
#define pb push_back
#define pii pair < int, int >
#define F first
#define S second
//#define int long long int
#define sync ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0)

#define endl '\n'
using namespace std;
const int N=2e5+100;
vector <pii> g[N];
ll vis[N];
ll ans=0;
ll dp[N][2];
void dfs(ll v,ll p,ll w){
    ll ma=-1e9;
    ll d=0;
    for (auto u : g[v]){
        if (u.F==p) continue;
        dfs(u.F,v,u.S);
        dp[v][1]+=dp[u.F][0];
        d+=dp[u.F][0];
        ma=max(ma,u.S+dp[u.F][1]-dp[u.F][0]);
    }
    if (p!=-1 && ma>-1e9){
        ll cnt=d+ma+w;
        dp[v][0]=max(dp[v][1],cnt);
    }
}
ll up[N][2];
ll dfs2(ll v,ll p){
    ll cnt=0,wp=0;
    for (auto u : g[v]){
        if (u.F==p){
            wp=u.S;
            continue;
        }
        cnt+=dp[u.F][0];
    }
    cnt+=up[v][0];
    for (auto u : g[v]){
        if (u.F==p) continue;
        up[u.F][1]=cnt-dp[u.F][0];
    }
    for (auto u : g[v]){
        if (u.F==p || v==1) continue;
        up[u.F][0]=max(up[u.F][0],u.S+wp+cnt-dp[u.F][0]-up[v][0]+up[v][1]);
    }
    ll mx=-1e9;
    for (auto u : g[v]){
        ll z=cnt;
        if (u.F==p) continue;
        /*
        for (auto q : g[v]){
            if (u.F==q.F || q.F==p) continue;
            ll t=z-dp[u.F][0]-dp[q.F][0]+dp[q.F][1]+u.S+q.S;
            up[u.F][0]=max(up[u.F][0],t);
        }
        */
        ll t=z+mx-dp[u.F][0]+u.S;
        up[u.F][0]=max(up[u.F][0],t);
        up[u.F][0]=max(up[u.F][0],up[u.F][1]);
        mx=max(mx,-dp[u.F][0]+dp[u.F][1]+u.S);
    }
    mx=-1e9;
    reverse(g[v].begin(),g[v].end());
    for (auto u : g[v]){
        ll z=cnt;
        if (u.F==p) continue;
        /*
        for (auto q : g[v]){
            if (u.F==q.F || q.F==p) continue;
            ll t=z-dp[u.F][0]-dp[q.F][0]+dp[q.F][1]+u.S+q.S;
            up[u.F][0]=max(up[u.F][0],t);
        }
        */
        ll t=z+mx-dp[u.F][0]+u.S;
        up[u.F][0]=max(up[u.F][0],t);
        up[u.F][0]=max(up[u.F][0],up[u.F][1]);
        mx=max(mx,-dp[u.F][0]+dp[u.F][1]+u.S);
    }
    for (auto u : g[v]){
        if (u.F!=p) dfs2(u.F,v);
    }
}
int32_t main(){
    sync;
    ll n;
    cin >> n;
    for (int i=0;i<n-1;i++){
        ll u,v,w;
        cin >> u >> v >> w;
        g[u].pb({v,w});
        g[v].pb({u,w});
    }
    for (int i=1;i<=n;i++){
        vector <pii> a;
        for (auto  q : g[i]){
           ll u=q.F;
            if (g[u].size()==1) a.pb({q.S,u});
        }
        sort(a.begin(),a.end());
        for (int j=1;j<a.size();j++){
            vis[a[j].S]=1;
        }
    }
    ll ma=0;
    ll cnt=0;
    dfs(1,-1,0);
    dfs2(1,1);
    for (int i=1;i<=n;i++){
        ma=max(ma,dp[i][1]+up[i][0]);
        //cout << i << " " << dp[i][1] << " " << up[i][0] << " " << ma << endl;
    }
    cout << ma << endl;
}
/*
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
*/
/*
6
1 2 20
2 3 20
3 4
10
3 5 10
3 6 10
*/

Compilation message

beads.cpp: In function 'll dfs2(ll, ll)':
beads.cpp:88:1: warning: no return statement in function returning non-void [-Wreturn-type]
 }
 ^
beads.cpp: In function 'int32_t main()':
beads.cpp:106:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (int j=1;j<a.size();j++){
                      ~^~~~~~~~~
beads.cpp:111:8: warning: unused variable 'cnt' [-Wunused-variable]
     ll cnt=0;
        ^~~

Subtask #1
13.0 / 13.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 4988 KB Output is correct
2 Correct 6 ms 4984 KB Output is correct
3 Correct 8 ms 5112 KB Output is correct
4 Correct 4 ms 4984 KB Output is correct
5 Correct 6 ms 4984 KB Output is correct
6 Correct 8 ms 5112 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 4984 KB Output is correct
10 Correct 6 ms 5112 KB Output is correct
11 Correct 6 ms 4984 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 4988 KB Output is correct
2 Correct 6 ms 4984 KB Output is correct
3 Correct 8 ms 5112 KB Output is correct
4 Correct 4 ms 4984 KB Output is correct
5 Correct 6 ms 4984 KB Output is correct
6 Correct 8 ms 5112 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 4984 KB Output is correct
10 Correct 6 ms 5112 KB Output is correct
11 Correct 6 ms 4984 KB Output is correct
12 Correct 6 ms 4984 KB Output is correct
13 Correct 6 ms 4984 KB Output is correct
14 Correct 6 ms 4984 KB Output is correct
15 Correct 6 ms 5116 KB Output is correct
16 Correct 7 ms 5112 KB Output is correct
17 Correct 7 ms 4984 KB Output is correct
18 Correct 6 ms 4984 KB Output is correct
19 Correct 7 ms 5112 KB Output is correct
20 Correct 6 ms 5040 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 7 ms 4988 KB Output is correct
2 Correct 6 ms 4984 KB Output is correct
3 Correct 8 ms 5112 KB Output is correct
4 Correct 4 ms 4984 KB Output is correct
5 Correct 6 ms 4984 KB Output is correct
6 Correct 8 ms 5112 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 4984 KB Output is correct
10 Correct 6 ms 5112 KB Output is correct
11 Correct 6 ms 4984 KB Output is correct
12 Correct 6 ms 4984 KB Output is correct
13 Correct 6 ms 4984 KB Output is correct
14 Correct 6 ms 4984 KB Output is correct
15 Correct 6 ms 5116 KB Output is correct
16 Correct 7 ms 5112 KB Output is correct
17 Correct 7 ms 4984 KB Output is correct
18 Correct 6 ms 4984 KB Output is correct
19 Correct 7 ms 5112 KB Output is correct
20 Correct 6 ms 5040 KB Output is correct
21 Correct 6 ms 5112 KB Output is correct
22 Correct 6 ms 5112 KB Output is correct
23 Correct 10 ms 5368 KB Output is correct
24 Correct 10 ms 5376 KB Output is correct
25 Correct 10 ms 5368 KB Output is correct
26 Correct 13 ms 5624 KB Output is correct
27 Correct 14 ms 5624 KB Output is correct
28 Correct 13 ms 5808 KB Output is correct
29 Correct 13 ms 5624 KB Output is correct
30 Correct 12 ms 5752 KB Output is correct
31 Correct 13 ms 6008 KB Output is correct

Subtask #4
43.0 / 43.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 4988 KB Output is correct
2 Correct 6 ms 4984 KB Output is correct
3 Correct 8 ms 5112 KB Output is correct
4 Correct 4 ms 4984 KB Output is correct
5 Correct 6 ms 4984 KB Output is correct
6 Correct 8 ms 5112 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 4984 KB Output is correct
10 Correct 6 ms 5112 KB Output is correct
11 Correct 6 ms 4984 KB Output is correct
12 Correct 6 ms 4984 KB Output is correct
13 Correct 6 ms 4984 KB Output is correct
14 Correct 6 ms 4984 KB Output is correct
15 Correct 6 ms 5116 KB Output is correct
16 Correct 7 ms 5112 KB Output is correct
17 Correct 7 ms 4984 KB Output is correct
18 Correct 6 ms 4984 KB Output is correct
19 Correct 7 ms 5112 KB Output is correct
20 Correct 6 ms 5040 KB Output is correct
21 Correct 6 ms 5112 KB Output is correct
22 Correct 6 ms 5112 KB Output is correct
23 Correct 10 ms 5368 KB Output is correct
24 Correct 10 ms 5376 KB Output is correct
25 Correct 10 ms 5368 KB Output is correct
26 Correct 13 ms 5624 KB Output is correct
27 Correct 14 ms 5624 KB Output is correct
28 Correct 13 ms 5808 KB Output is correct
29 Correct 13 ms 5624 KB Output is correct
30 Correct 12 ms 5752 KB Output is correct
31 Correct 13 ms 6008 KB Output is correct
32 Correct 46 ms 8696 KB Output is correct
33 Correct 47 ms 8612 KB Output is correct
34 Correct 48 ms 8680 KB Output is correct
35 Correct 273 ms 20088 KB Output is correct
36 Correct 275 ms 19932 KB Output is correct
37 Correct 266 ms 19872 KB Output is correct
38 Correct 217 ms 20564 KB Output is correct
39 Correct 190 ms 19692 KB Output is correct
40 Correct 206 ms 20308 KB Output is correct
41 Correct 264 ms 23448 KB Output is correct