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Submission #918514

# Submission time Handle Problem Language Result Execution time Memory
918514 2024-01-30T03:27:09 Z Boycl07 Beads and wires (APIO14_beads) C++17
100 / 100
 279 ms 42648 KB 
#include <bits/stdc++.h>

using namespace std;

typedef long long ll;

#define rep(i, n) for(int i = 1; i <= n; ++i)
#define forn(i, l, r) for(int i = l; i <= r; ++i)
#define ford(i, r, l) for(int i = r; i >= l; --i)
#define FOR(i, n) for(int i = 0; i < n; ++i)
#define fi first
#define se second
#define pii pair<int, int>
#define pll pair<ll, ll>
#define pb push_back
#define endl "\n"
#define task "beads"
#define sz(a) int(a.size())
#define C(x, y) make_pair(x, y)
#define all(a) (a).begin(), (a).end()
#define bit(i, mask) (mask >> i & 1)

template<typename T> bool maximize(T &res, const T &val) { if (res < val){ res = val; return true; }; return false; }
template<typename T> bool minimize(T &res, const T &val) { if (res > val){ res = val; return true; }; return false; }

inline int readInt()       {char c;while(c=getchar(),c!='-'&&(c<'0'||c>'9'));bool sign=(c=='-');if(sign)c=getchar();int n=c-'0';while(c=getchar(),c>='0'&&c<='9')n=10*n+c-'0';return(!sign)?n:-n;}
inline ll readLong()       {char c;while(c=getchar(),c!='-'&&(c<'0'||c>'9'));bool sign=(c=='-');if(sign)c=getchar();ll  n=c-'0';while(c=getchar(),c>='0'&&c<='9')n=10*n+c-'0';return(!sign)?n:-n;}
inline string readString() {char c;while(c=getchar(),c==' '||c=='\n'||c=='\t');string s({c});while(c=getchar(),c!=EOF&&c!=' '&&c!='\n'&&c!='\t')s+=c;return s;}


const int N = 2e5 + 4;
const int M = 3e5 + 3;
const int K = 22;
const int INF = 1e9 + 3;
const ll LINF = 1e18;

int n;

int dp[N][2];
int cnt[N], sum[N];
multiset<int> s[N];


vector<pii> g[N];

void dfs(int u, int p)
{
    dp[u][0] = 0; dp[u][1] = -INF;
    for(pii e : g[u])
    {
        int v = e.fi, w = e.se;
        if(v == p) continue;
        dfs(v, u);
        ++cnt[u];
        dp[u][0] += max(dp[v][0], dp[v][1] + w);
    }


    for(pii e : g[u])
    {
        int v = e.fi, w = e.se;
        if(v == p) continue;
        int diff = dp[v][0] + w - max(dp[v][0], dp[v][1] + w);
        s[u].insert(diff);
    }
    if(cnt[u] >= 1) dp[u][1] = dp[u][0] + *(--s[u].end());
    else dp[u][1] = -INF;
}

void change(int u, int v, int w)
{
    int diff;
    --cnt[u];
    dp[u][0] -= max(dp[v][0], dp[v][1] + w);
    diff = dp[v][0] + w - max(dp[v][0], dp[v][1] + w);
    s[u].erase(s[u].find(diff));

    if(cnt[u] >= 1) dp[u][1] = dp[u][0] + *(--s[u].end());
    else dp[u][1] = -INF;


    ++cnt[v];
    dp[v][0] += max(dp[u][0], dp[u][1] + w);
    diff = dp[u][0] + w - max(dp[u][0], dp[u][1] + w);
    s[v].insert(diff);

    if(cnt[v] >= 1) dp[v][1] = dp[v][0] + *(--s[v].end());
    else dp[v][1] = -INF;

}

int res = 0;

void dfs_reroot(int u, int p)
{
    maximize(res, dp[u][0]);
    for(pii e : g[u])
    {
        int v = e.fi, w = e.se;
        if(v == p) continue;
        change(u, v, w);
        dfs_reroot(v, u);
        change(v, u, w);
    }
}

void solve()
{
    cin >> n;
    rep(i, n - 1)
    {
        int u, v, w;
        cin >> u >> v >> w;
        g[u].pb({v, w});
        g[v].pb({u, w});
    }
    dfs(1, 1);
    dfs_reroot(1, 1);
    cout << res;
}

signed main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);

    int TC = 1;

    if(fopen(task".inp", "r"))
    {
        freopen(task".inp", "r", stdin);
        freopen(task"_slow.out", "w", stdout);
    }


    while(TC--)
    {
        solve();
        cout << endl;
    }

    return 0;
}

Compilation message

beads.cpp: In function 'int main()':
beads.cpp:131:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  131 |         freopen(task".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
beads.cpp:132:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  132 |         freopen(task"_slow.out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
13.0 / 13.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 16988 KB Output is correct
2 Correct 4 ms 16988 KB Output is correct
3 Correct 4 ms 16988 KB Output is correct
4 Correct 4 ms 16988 KB Output is correct
5 Correct 5 ms 17016 KB Output is correct
6 Correct 4 ms 16988 KB Output is correct
7 Correct 6 ms 16988 KB Output is correct
8 Correct 4 ms 16984 KB Output is correct
9 Correct 4 ms 17012 KB Output is correct
10 Correct 4 ms 16988 KB Output is correct
11 Correct 5 ms 16988 KB Output is correct
12 Correct 5 ms 16988 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 16988 KB Output is correct
2 Correct 4 ms 16988 KB Output is correct
3 Correct 4 ms 16988 KB Output is correct
4 Correct 4 ms 16988 KB Output is correct
5 Correct 5 ms 17016 KB Output is correct
6 Correct 4 ms 16988 KB Output is correct
7 Correct 6 ms 16988 KB Output is correct
8 Correct 4 ms 16984 KB Output is correct
9 Correct 4 ms 17012 KB Output is correct
10 Correct 4 ms 16988 KB Output is correct
11 Correct 5 ms 16988 KB Output is correct
12 Correct 5 ms 16988 KB Output is correct
13 Correct 4 ms 16988 KB Output is correct
14 Correct 4 ms 16988 KB Output is correct
15 Correct 4 ms 16984 KB Output is correct
16 Correct 5 ms 16988 KB Output is correct
17 Correct 4 ms 16984 KB Output is correct
18 Correct 5 ms 16988 KB Output is correct
19 Correct 4 ms 16988 KB Output is correct
20 Correct 4 ms 16984 KB Output is correct
21 Correct 6 ms 16988 KB Output is correct
22 Correct 5 ms 16988 KB Output is correct

Subtask #3
29.0 / 29.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 16988 KB Output is correct
2 Correct 4 ms 16988 KB Output is correct
3 Correct 4 ms 16988 KB Output is correct
4 Correct 4 ms 16988 KB Output is correct
5 Correct 5 ms 17016 KB Output is correct
6 Correct 4 ms 16988 KB Output is correct
7 Correct 6 ms 16988 KB Output is correct
8 Correct 4 ms 16984 KB Output is correct
9 Correct 4 ms 17012 KB Output is correct
10 Correct 4 ms 16988 KB Output is correct
11 Correct 5 ms 16988 KB Output is correct
12 Correct 5 ms 16988 KB Output is correct
13 Correct 4 ms 16988 KB Output is correct
14 Correct 4 ms 16988 KB Output is correct
15 Correct 4 ms 16984 KB Output is correct
16 Correct 5 ms 16988 KB Output is correct
17 Correct 4 ms 16984 KB Output is correct
18 Correct 5 ms 16988 KB Output is correct
19 Correct 4 ms 16988 KB Output is correct
20 Correct 4 ms 16984 KB Output is correct
21 Correct 6 ms 16988 KB Output is correct
22 Correct 5 ms 16988 KB Output is correct
23 Correct 8 ms 17240 KB Output is correct
24 Correct 7 ms 17472 KB Output is correct
25 Correct 8 ms 17244 KB Output is correct
26 Correct 9 ms 17756 KB Output is correct
27 Correct 9 ms 17756 KB Output is correct
28 Correct 11 ms 17756 KB Output is correct
29 Correct 10 ms 17752 KB Output is correct
30 Correct 11 ms 17920 KB Output is correct
31 Correct 12 ms 18268 KB Output is correct

Subtask #4
43.0 / 43.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 16988 KB Output is correct
2 Correct 4 ms 16988 KB Output is correct
3 Correct 4 ms 16988 KB Output is correct
4 Correct 4 ms 16988 KB Output is correct
5 Correct 5 ms 17016 KB Output is correct
6 Correct 4 ms 16988 KB Output is correct
7 Correct 6 ms 16988 KB Output is correct
8 Correct 4 ms 16984 KB Output is correct
9 Correct 4 ms 17012 KB Output is correct
10 Correct 4 ms 16988 KB Output is correct
11 Correct 5 ms 16988 KB Output is correct
12 Correct 5 ms 16988 KB Output is correct
13 Correct 4 ms 16988 KB Output is correct
14 Correct 4 ms 16988 KB Output is correct
15 Correct 4 ms 16984 KB Output is correct
16 Correct 5 ms 16988 KB Output is correct
17 Correct 4 ms 16984 KB Output is correct
18 Correct 5 ms 16988 KB Output is correct
19 Correct 4 ms 16988 KB Output is correct
20 Correct 4 ms 16984 KB Output is correct
21 Correct 6 ms 16988 KB Output is correct
22 Correct 5 ms 16988 KB Output is correct
23 Correct 8 ms 17240 KB Output is correct
24 Correct 7 ms 17472 KB Output is correct
25 Correct 8 ms 17244 KB Output is correct
26 Correct 9 ms 17756 KB Output is correct
27 Correct 9 ms 17756 KB Output is correct
28 Correct 11 ms 17756 KB Output is correct
29 Correct 10 ms 17752 KB Output is correct
30 Correct 11 ms 17920 KB Output is correct
31 Correct 12 ms 18268 KB Output is correct
32 Correct 34 ms 21852 KB Output is correct
33 Correct 33 ms 21844 KB Output is correct
34 Correct 33 ms 21804 KB Output is correct
35 Correct 201 ms 38228 KB Output is correct
36 Correct 212 ms 37972 KB Output is correct
37 Correct 191 ms 38020 KB Output is correct
38 Correct 252 ms 38336 KB Output is correct
39 Correct 238 ms 38192 KB Output is correct
40 Correct 260 ms 38236 KB Output is correct
41 Correct 279 ms 42648 KB Output is correct