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Submission #525217

# Submission time Handle Problem Language Result Execution time Memory
525217 2022-02-11T06:11:46 Z XII Beads and wires (APIO14_beads) C++17
100 / 100
 183 ms 29112 KB 
#include <bits/stdc++.h>
using namespace std;

using ll = long long;

#define fi first
#define se second
#define mp make_pair
#define eb emplace_back
#define ALL(x) (x).begin(), (x).end()

#define FOR(i, a, b) for(int i = (a); i < (b); ++i)
#define FORU(i, a, b) for(int i = (a); i <= (b); ++i)
#define FORD(i, a, b) for(int i = (a); i >= (b); --i)

#define IOS cin.tie(0)->sync_with_stdio(false);
#define PROB "APIO14_beads"
void Fi(){
    if(fopen(PROB".inp", "r")){
        freopen(PROB".inp", "r", stdin);
        freopen(PROB".out", "w", stdout);
    }
}

const int N = 2e5 + 1;
const ll INF = 1e15;
int n;
ll dp[2][N];
using pi = pair<int, int>;
vector<pi> adj[N];

int tc[2][N];
ll f[2][N], dif[2][N];
ll ans;

void dfs1(int u, int p){
    dif[0][u] = dif[1][u] = -INF;
    for(auto [w, v]: adj[u]) if(v != p){
        dfs1(v, u);
        f[0][u] += max(f[0][v], f[1][v] + w);
        ll diftmp = (f[0][v] + w) - max(f[0][v], f[1][v] + w);
        if(dif[0][u] < diftmp){
            dif[1][u] = dif[0][u];
            tc[1][u] = tc[0][u];

            dif[0][u] = diftmp;
            tc[0][u] = v;
        } else if(dif[1][u] < diftmp){
            dif[1][u] = diftmp;
            tc[1][u] = v;
        }
    }
    f[1][u] = f[0][u] + dif[0][u];
//    cout << u << " " << f[0][u] << " " << f[1][u] << "\n";
//    cout << dif[0][u] << " " << dif[1][u] << "\n\n";
}

void dfs2(int u, int p, ll wei, ll down[2]){
    ll tot = f[0][u] + max(down[0], down[1] + wei);
    ll diftmp = (down[0] + wei) - max(down[0], down[1] + wei);
    ans = max(ans, tot);
//    cout << u << " " << down[0] << " " << down[1] << " " << tot << " " << diftmp << "\n";
    for(auto [w, v]: adj[u]) if(v != p){
        ll dwn[2];
        dwn[0] = tot - max(f[0][v], f[1][v] + w);
        if(v != tc[0][u]){
            dwn[1] = dwn[0] + max(dif[0][u], diftmp);
        } else{
            dwn[1] = dwn[0] + max(dif[1][u], diftmp);
        }
        dfs2(v, u, w, dwn);
    }
}

int main(){
    IOS;
    Fi();
    cin >> n;
    FOR(i, 1, n){
        int u, v, w;
        cin >> u >> v >> w;
        adj[u].eb(w, v);
        adj[v].eb(w, u);
    }
    dfs1(1, -1);
    ll down[2] = {0, -INF};
    dfs2(1, -1, -INF, down);
    cout << ans;
    return 0;
}

Compilation message

beads.cpp: In function 'void Fi()':
beads.cpp:20:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   20 |         freopen(PROB".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
beads.cpp:21:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   21 |         freopen(PROB".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
13.0 / 13.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 5020 KB Output is correct
2 Correct 3 ms 5024 KB Output is correct
3 Correct 3 ms 5028 KB Output is correct
4 Correct 3 ms 5024 KB Output is correct
5 Correct 3 ms 5004 KB Output is correct
6 Correct 3 ms 5024 KB Output is correct
7 Correct 3 ms 4940 KB Output is correct
8 Correct 3 ms 4940 KB Output is correct
9 Correct 3 ms 5024 KB Output is correct
10 Correct 4 ms 5032 KB Output is correct
11 Correct 3 ms 5040 KB Output is correct
12 Correct 3 ms 5064 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 5020 KB Output is correct
2 Correct 3 ms 5024 KB Output is correct
3 Correct 3 ms 5028 KB Output is correct
4 Correct 3 ms 5024 KB Output is correct
5 Correct 3 ms 5004 KB Output is correct
6 Correct 3 ms 5024 KB Output is correct
7 Correct 3 ms 4940 KB Output is correct
8 Correct 3 ms 4940 KB Output is correct
9 Correct 3 ms 5024 KB Output is correct
10 Correct 4 ms 5032 KB Output is correct
11 Correct 3 ms 5040 KB Output is correct
12 Correct 3 ms 5064 KB Output is correct
13 Correct 3 ms 5080 KB Output is correct
14 Correct 3 ms 5024 KB Output is correct
15 Correct 3 ms 5068 KB Output is correct
16 Correct 4 ms 5012 KB Output is correct
17 Correct 3 ms 5028 KB Output is correct
18 Correct 3 ms 5068 KB Output is correct
19 Correct 3 ms 5068 KB Output is correct
20 Correct 3 ms 5068 KB Output is correct
21 Correct 3 ms 5068 KB Output is correct
22 Correct 3 ms 5068 KB Output is correct

Subtask #3
29.0 / 29.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 5020 KB Output is correct
2 Correct 3 ms 5024 KB Output is correct
3 Correct 3 ms 5028 KB Output is correct
4 Correct 3 ms 5024 KB Output is correct
5 Correct 3 ms 5004 KB Output is correct
6 Correct 3 ms 5024 KB Output is correct
7 Correct 3 ms 4940 KB Output is correct
8 Correct 3 ms 4940 KB Output is correct
9 Correct 3 ms 5024 KB Output is correct
10 Correct 4 ms 5032 KB Output is correct
11 Correct 3 ms 5040 KB Output is correct
12 Correct 3 ms 5064 KB Output is correct
13 Correct 3 ms 5080 KB Output is correct
14 Correct 3 ms 5024 KB Output is correct
15 Correct 3 ms 5068 KB Output is correct
16 Correct 4 ms 5012 KB Output is correct
17 Correct 3 ms 5028 KB Output is correct
18 Correct 3 ms 5068 KB Output is correct
19 Correct 3 ms 5068 KB Output is correct
20 Correct 3 ms 5068 KB Output is correct
21 Correct 3 ms 5068 KB Output is correct
22 Correct 3 ms 5068 KB Output is correct
23 Correct 5 ms 5452 KB Output is correct
24 Correct 5 ms 5420 KB Output is correct
25 Correct 5 ms 5420 KB Output is correct
26 Correct 6 ms 5924 KB Output is correct
27 Correct 7 ms 5840 KB Output is correct
28 Correct 6 ms 5964 KB Output is correct
29 Correct 6 ms 5808 KB Output is correct
30 Correct 6 ms 5944 KB Output is correct
31 Correct 7 ms 6432 KB Output is correct

Subtask #4
43.0 / 43.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 5020 KB Output is correct
2 Correct 3 ms 5024 KB Output is correct
3 Correct 3 ms 5028 KB Output is correct
4 Correct 3 ms 5024 KB Output is correct
5 Correct 3 ms 5004 KB Output is correct
6 Correct 3 ms 5024 KB Output is correct
7 Correct 3 ms 4940 KB Output is correct
8 Correct 3 ms 4940 KB Output is correct
9 Correct 3 ms 5024 KB Output is correct
10 Correct 4 ms 5032 KB Output is correct
11 Correct 3 ms 5040 KB Output is correct
12 Correct 3 ms 5064 KB Output is correct
13 Correct 3 ms 5080 KB Output is correct
14 Correct 3 ms 5024 KB Output is correct
15 Correct 3 ms 5068 KB Output is correct
16 Correct 4 ms 5012 KB Output is correct
17 Correct 3 ms 5028 KB Output is correct
18 Correct 3 ms 5068 KB Output is correct
19 Correct 3 ms 5068 KB Output is correct
20 Correct 3 ms 5068 KB Output is correct
21 Correct 3 ms 5068 KB Output is correct
22 Correct 3 ms 5068 KB Output is correct
23 Correct 5 ms 5452 KB Output is correct
24 Correct 5 ms 5420 KB Output is correct
25 Correct 5 ms 5420 KB Output is correct
26 Correct 6 ms 5924 KB Output is correct
27 Correct 7 ms 5840 KB Output is correct
28 Correct 6 ms 5964 KB Output is correct
29 Correct 6 ms 5808 KB Output is correct
30 Correct 6 ms 5944 KB Output is correct
31 Correct 7 ms 6432 KB Output is correct
32 Correct 27 ms 9604 KB Output is correct
33 Correct 28 ms 9508 KB Output is correct
34 Correct 26 ms 9516 KB Output is correct
35 Correct 183 ms 23712 KB Output is correct
36 Correct 161 ms 23824 KB Output is correct
37 Correct 166 ms 23804 KB Output is correct
38 Correct 106 ms 24244 KB Output is correct
39 Correct 103 ms 21112 KB Output is correct
40 Correct 112 ms 24100 KB Output is correct
41 Correct 156 ms 29112 KB Output is correct