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Submission #960964

# Submission time Handle Problem Language Result Execution time Memory
960964 2024-04-11T10:02:42 Z Ghetto Chase (CEOI17_chase) C++17
100 / 100
 3234 ms 120336 KB 
#include <bits/stdc++.h>
using namespace std;
using pii = pair<int, int>;
using lint = long long;
const int MAX_N = 1e5 + 5, MAX_K = 1e2 + 5;

int n, k;
lint val[MAX_N];
vector<int> adj[MAX_N], adj_ind[MAX_N]; // adj_ind[u][i] = ind of adj list u is for adj[u][i]

int par[MAX_N];
vector<int> children[MAX_N];
void init1() {
    for (int i = 1; i <= n; i++) children[i].push_back(0);
}
int child_ind[MAX_N];

int n_inds, ind[MAX_N], rev_ind[MAX_N];
void dfs(int u) {
    ind[u] = ++n_inds;
    rev_ind[ind[u]] = u;
    for (int v : adj[u]) {
        if (ind[v]) continue;
        par[v] = u;
        children[u].push_back(v);
        child_ind[v] = children[u].size() - 1;
        dfs(v);
    }
}

lint val_sum[MAX_N];

void precomp() {
    init1();

    dfs(1);

    for (int i = 1; i <= n; i++)
        for (int j : adj[i]) val_sum[i] += val[j];
}

lint dp1[MAX_N][MAX_K];
vector<lint> dp2[MAX_N][2];
lint max_dp2[MAX_N][2];
void init2() {
    for (int i = 1; i <= n; i++)
        for (int c = 0; c <= 1; c++)
            dp2[i][c].resize(adj[i].size() + 2);
}

lint pref_max[MAX_N], suff_max[MAX_N];

int main() {
    // freopen("chase.in", "r", stdin);

    cin >> n >> k;
    for (int i = 1; i <= n; i++) cin >> val[i];
    for (int i = 1; i < n; i++) {
        int u, v; cin >> u >> v;
        adj[u].push_back(v);
        adj[v].push_back(u);
    }

    precomp();

    for (int c = 1; c <= k; c++) {
        for (int i = n; i >= 1; i--) {
            int u = rev_ind[i];

            lint leave = 0;
            for (int v : children[u])
                if (v != 0) leave = max(leave, dp1[v][c]);

            lint take = 0; 
            for (int v : children[u])
                if (v != 0) take = max(take, dp1[v][c - 1]);
            take += val_sum[u] - val[par[u]];

            dp1[u][c] = max(take, leave);
        }
    }

    init2();
    lint ans = 0;
    for (int c = 0; c <= k; c++) {
        int opp_c = k - c;
        int p = c % 2, opp_p = (c + 1) % 2;
        for (int i = n; i >= 1; i--) {
            int u = rev_ind[i];

            max_dp2[u][p] = 0;
            for (int j = 0; j < children[u].size(); j++) {
                pref_max[j] = max(((j == 0) ? 0 : pref_max[j - 1]), dp1[children[u][j]][opp_c]);
                if (c == 0) continue;
                int v = children[u][j];

                lint leave = (v == 0) ? 0 : max_dp2[v][p];
                lint take = val_sum[u] - val[v] + ((v == 0) ? 0 : max_dp2[v][opp_p]);
                dp2[u][p][j] = max(take, leave);
                max_dp2[u][p] = max(max_dp2[u][p], dp2[u][p][j]);
            }

            for (int j = children[u].size() - 1; j >= 0; j--) 
                suff_max[j] = max((j == children[u].size() - 1) ? 0 : suff_max[j + 1], dp1[children[u][j]][opp_c]);
            
            for (int j = 0; j < children[u].size(); j++) {               
                lint tot_max = (j == 0) ? 0 : pref_max[j - 1];
                tot_max = max(tot_max, ((j == children[u].size() - 1) ? 0 : suff_max[j + 1]));

                ans = max(ans, dp2[u][p][j] + tot_max);
            }
        }
    }
    cout << ans << '\n';
    
}

Compilation message

chase.cpp: In function 'int main()':
chase.cpp:92:31: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   92 |             for (int j = 0; j < children[u].size(); j++) {
      |                             ~~^~~~~~~~~~~~~~~~~~~~
chase.cpp:104:38: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  104 |                 suff_max[j] = max((j == children[u].size() - 1) ? 0 : suff_max[j + 1], dp1[children[u][j]][opp_c]);
      |                                    ~~^~~~~~~~~~~~~~~~~~~~~~~~~
chase.cpp:106:31: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  106 |             for (int j = 0; j < children[u].size(); j++) {
      |                             ~~^~~~~~~~~~~~~~~~~~~~
chase.cpp:108:44: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  108 |                 tot_max = max(tot_max, ((j == children[u].size() - 1) ? 0 : suff_max[j + 1]));
      |                                          ~~^~~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 17500 KB Output is correct
2 Correct 4 ms 17580 KB Output is correct
3 Correct 4 ms 17500 KB Output is correct
4 Correct 4 ms 17500 KB Output is correct
5 Correct 3 ms 17500 KB Output is correct
6 Correct 4 ms 17496 KB Output is correct

Subtask #2
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 17500 KB Output is correct
2 Correct 4 ms 17580 KB Output is correct
3 Correct 4 ms 17500 KB Output is correct
4 Correct 4 ms 17500 KB Output is correct
5 Correct 3 ms 17500 KB Output is correct
6 Correct 4 ms 17496 KB Output is correct
7 Correct 8 ms 19840 KB Output is correct
8 Correct 5 ms 19956 KB Output is correct
9 Correct 5 ms 19804 KB Output is correct
10 Correct 12 ms 19804 KB Output is correct
11 Correct 6 ms 19804 KB Output is correct
12 Correct 5 ms 19804 KB Output is correct

Subtask #3
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 2056 ms 118204 KB Output is correct
2 Correct 1951 ms 118184 KB Output is correct
3 Correct 669 ms 115504 KB Output is correct
4 Correct 159 ms 115272 KB Output is correct
5 Correct 2812 ms 115272 KB Output is correct
6 Correct 2850 ms 115268 KB Output is correct
7 Correct 3047 ms 115264 KB Output is correct

Subtask #4
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 17500 KB Output is correct
2 Correct 4 ms 17580 KB Output is correct
3 Correct 4 ms 17500 KB Output is correct
4 Correct 4 ms 17500 KB Output is correct
5 Correct 3 ms 17500 KB Output is correct
6 Correct 4 ms 17496 KB Output is correct
7 Correct 8 ms 19840 KB Output is correct
8 Correct 5 ms 19956 KB Output is correct
9 Correct 5 ms 19804 KB Output is correct
10 Correct 12 ms 19804 KB Output is correct
11 Correct 6 ms 19804 KB Output is correct
12 Correct 5 ms 19804 KB Output is correct
13 Correct 2056 ms 118204 KB Output is correct
14 Correct 1951 ms 118184 KB Output is correct
15 Correct 669 ms 115504 KB Output is correct
16 Correct 159 ms 115272 KB Output is correct
17 Correct 2812 ms 115272 KB Output is correct
18 Correct 2850 ms 115268 KB Output is correct
19 Correct 3047 ms 115264 KB Output is correct
20 Correct 3234 ms 117364 KB Output is correct
21 Correct 120 ms 35668 KB Output is correct
22 Correct 2608 ms 117360 KB Output is correct
23 Correct 180 ms 117244 KB Output is correct
24 Correct 2943 ms 117360 KB Output is correct
25 Correct 649 ms 117240 KB Output is correct
26 Correct 1919 ms 120336 KB Output is correct
27 Correct 1882 ms 120336 KB Output is correct