Submission #900504

#	Time	Username	Problem	Language	Result	Execution time	Memory
900504		Trisanu_Das	Magic Tree (CEOI19_magictree)	C++17	14 / 100	141 ms	128848 KiB

magictree

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define all(x) (x).begin(), (x).end()
#define MP make_pair
const int N = 100500;

struct fenwick {
    vector<int> f;
    fenwick(int n) : f(n + 2) {}
    void add(int i, int x) {
        i++;
        while (i < f.size()) f[i] = max(f[i], x), i += -i & i;
    }
    int get(int i) {
        i++;
        int res = 0;
        while (i > 0) res = max(res, f[i]), i -= -i & i;
        return res;
    }
};

vector<int> g[N];
vector<vector<ll>> dp;
pair<int, int> fruit[N];

void dfs(int v) {
    dp[v][fruit[v].first] = fruit[v].second;
    for (int u : g[v]) dfs(u);
    for (int t = 1; t < dp[v].size(); t++) dp[v][t] += dp[v][t - 1];
    for (int t = 1; t < dp[v].size(); t++) dp[v][t] = max(dp[v][t], dp[v][t - 1]);
}

int LIS(const vector<int> &a) {
    int n = a.size();
    fenwick f(2e5);
    int res = 0;
    for (int i = 0; i < n; i++) {
        int _dp = f.get(a[i]) + 1;
        f.add(a[i], _dp);
        res = max(res, _dp);
    }
    return res;
}

void solve() {
    int n, m, k;
    cin >> n >> m >> k;
    ll sum = 0;
    bool sub3 = true;
    for (int i = 1; i < n; i++) {
        int p;
        cin >> p;
        --p;
        if (p != i - 1) sub3 = false;
        g[p].push_back(i);
    }
    map<int, int> mp;
    vector<int> a(n);
    for (int i = 0; i < m; i++) {
        int v, d, w;
        cin >> v >> d >> w;
        --v;
        mp[d];
        fruit[v] = MP(d, w);
        sum += w;
        a[v] = d;
        if (w != 1) sub3 = false;
    }
    if (sub3) {
        vector<int> b;
        for (int x : a) if (x != 0) b.push_back(x);
        reverse(all(b));
        cout << LIS(b) << endl;
        return;
    }
    mp[0];
    k = 0;
    for (auto &now : mp) now.second = ++k;
    for (int i = 0; i < n; i++) fruit[i].first = mp[fruit[i].first];
    if (k > 1000) {
        cout << sum << '\n';
        return;
    }
    dp.assign(n, vector<ll>(k + 1, 0));
    dfs(0);
    cout << dp[0].back() << endl;
}

int main() {
    ios_base::sync_with_stdio(false); cin.tie(NULL);
    solve();
}

Compilation message (stderr)

magictree.cpp: In member function 'void fenwick::add(int, int)':
magictree.cpp:13:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   13 |         while (i < f.size()) f[i] = max(f[i], x), i += -i & i;
      |                ~~^~~~~~~~~~
magictree.cpp: In function 'void dfs(int)':
magictree.cpp:30:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   30 |     for (int t = 1; t < dp[v].size(); t++) dp[v][t] += dp[v][t - 1];
      |                     ~~^~~~~~~~~~~~~~
magictree.cpp:31:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   31 |     for (int t = 1; t < dp[v].size(); t++) dp[v][t] = max(dp[v][t], dp[v][t - 1]);
      |                     ~~^~~~~~~~~~~~~~

• Subtask 1: 0 / 6
• Subtask 2: 3 / 3
• Subtask 3: 11 / 11
• Subtask 4: 0 / 12
• Subtask 5: 0 / 16
• Subtask 6: 0 / 13
• Subtask 7: 0 / 22
• Subtask 8: 0 / 17