Submission #852953

#	Time	Username	Problem	Language	Result	Execution time	Memory
852953		thanh913	Chase (CEOI17_chase)	C++14	0 / 100	78 ms	95528 KiB

chase

#include <bits/stdc++.h>
using namespace std;

#define fi first
#define se second
using ll = long long;

const int N = 1e5+5;

//--------------------------------------
int n, k, a[N];
vector<int> adj[N];

ll f[N][105][2];
void dfs(int u, int pr) {
    ll s = 0;
    for (int i = 0; i < adj[u].size(); i++) {
        if (adj[u][i] == pr) {
            swap(adj[u][i], adj[u].back());
            adj[u].pop_back();
        }
    }
    for (auto v : adj[u]) {
        dfs(v, u);
        s += a[v];
    }
    for (auto v : adj[u]) {
        if (v == pr) continue;
        for (int i = 0; i <= k; i++) {
            f[u][i][0] = max(f[v][i][0], f[v][i][1] + a[u]);
            if (i) {
                f[u][i][1] = max(f[v][i-1][0], f[v][i-1][1]) + s - a[v];
            }
        }
    }
}

vector<vector<array<int, 2>>> trai, phai;
void dfs2(int u, int pr) {
    ll s = 0;
    trai.assign(adj[u].size()+1, vector<array<int, 2>>(k+1, {0, 0})); phai = trai;
    vector<array<int, 2>> ins; ins.reserve(adj[u].size());
    for (int i = 0; i < n; i++) {
        // ins.push_back({f[v][]});
    }
    for (auto v : adj[u]) {
        if (v == pr) continue;
        for (int i = 0; i <= k; i++) {
            f[u][i][0] = max(f[v][i][0], f[v][i][1]);
            if (i) {
                f[u][i][1] = max(f[v][i-1][0], f[v][i-1][1]) + s - a[v];
            }
        }
    }
}

int main() {
    ios::sync_with_stdio(0);
    cin.tie(0), cout.tie(0);
    cin >> n >> k;
    for (int i = 1; i <= n; i++) cin >> a[i];
    for (int i = 1; i < n; i++) {
        int u, v; cin >> u >> v;
        adj[u].push_back(v);
        adj[v].push_back(u);
    }
    dfs(1, 1);
    ll ans = 0;
    for (int i = 0; i <= 100; i++) {
        ans = max({ans, f[1][i][0], f[1][i][1]});
    }
    cout << ans;
}
/*
f(u, i, 0) = f(v, i, 0), f(v, i, 1)
f(u, i, 1) = f(v, i-1, 0) + tong con khac v
           = f(v, i-1, 1) + tong con khac v


*/

Compilation message (stderr)

chase.cpp: In function 'void dfs(int, int)':
chase.cpp:17:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   17 |     for (int i = 0; i < adj[u].size(); i++) {
      |                     ~~^~~~~~~~~~~~~~~

• Subtask 1: 0 / 20
• Subtask 2: 0 / 20
• Subtask 3: 0 / 30
• Subtask 4: 0 / 30