Submission #1344406

#	Time	Username	Problem	Language	Result	Execution time	Memory
1344406		nghiaxtoneri	Chase (CEOI17_chase)	C++20	40 / 100	318 ms	589824 KiB

chase

#include <bits/stdc++.h>
#define int long long
#define endl '\n'
#define MASK(n) (1LL << n)
#define PhTrNghia "Chase"

using namespace std;

const int maxn = 2e5 + 5;
const int maxk = 205;
const int inf = 1e18;

int n, k;
int a[maxn];
int dp[maxn][maxk][2], s[maxn];
vector <int> g[maxn];

namespace sub2{
    int ans = 0;

    void dfs(int u, int p){
        for (int i = 0; i <= k; i++) ans = max(ans, dp[u][i][1]);

        for (int v: g[u]){
            if (v == p) continue;
            dp[v][0][0] = dp[u][0][0];

            for (int i = 1; i <= k; i++){
                dp[v][i][0] = max({dp[v][i][0], dp[u][i][0], dp[u][i][1]});

                int val = s[v] - a[u];
                dp[v][i][1] = max({dp[v][i][1], dp[u][i-1][1] + val, dp[u][i-1][0] + val});
            }

            dfs(v, u);
        }

        for (int i = 0; i <= k; i++){
            dp[u][i][0] = -inf;
            dp[u][i][1] = -inf;
        }
    }

    void solve(){
        for(int i = 1; i <= n; i++){
            dp[i][0][0] = 0;
            dp[i][1][1] = s[i];
            dfs(i, 0);
        }
        cout << ans;
    }
}

namespace sub3{
    int ans = 0;

    void dfs(int u, int p){
        for (int i = 0; i <= k; i++) ans = max(ans, dp[u][i][1]);

        for (int v: g[u]){
            if (v == p) continue;

            dp[v][0][0] = dp[u][0][0];

            for (int i = 1; i <= k; i++){
                dp[v][i][0] = max({dp[v][i][0], dp[u][i][0], dp[u][i][1]});

                int val = s[v] - a[u];
                dp[v][i][1] = max({dp[v][i][1], dp[u][i-1][1] + val, dp[u][i-1][0] + val});
            }

            dfs(v, u);
        }
    }

    void solve(){
        memset(dp, -0x3f, sizeof dp);
        dp[1][0][0] = 0;
        dp[1][1][1] = s[1];

        dfs(1, 0);

        cout << ans;
    }
}

signed main(){
    ios_base::sync_with_stdio(false);
    cin.tie(0); cout.tie(0);
    if (fopen(PhTrNghia".INP", "r")){
        freopen(PhTrNghia".INP", "r", stdin);
        freopen(PhTrNghia".OUT", "w", stdout);
    }

    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;
        g[u].push_back(v);
        g[v].push_back(u);
        s[u] += a[v];
        s[v] += a[u];
    }


    if (n <= 1000) sub2::solve(); else sub3::solve();

    return 0;
}
/*
12 2
2 3 3 8 1 5 6 7 8 3 5 4
2 1
2 7
3 4
4 7
7 6
5 6
6 8
6 9
7 10
10 11
10 12
*/

Compilation message (stderr)

chase.cpp: In function 'int main()':
chase.cpp:91:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   91 |         freopen(PhTrNghia".INP", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
chase.cpp:92:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   92 |         freopen(PhTrNghia".OUT", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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