Submission #136342

#	Time	Username	Problem	Language	Result	Execution time	Memory
136342		BThero	Chase (CEOI17_chase)	C++17	100 / 100	751 ms	342236 KiB

chase

// Why am I so dumb? :c
// chrono::system_clock::now().time_since_epoch().count()

//#pragma GCC optimize("Ofast")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")

#include<bits/stdc++.h>
#include<ext/pb_ds/assoc_container.hpp>
#include<ext/pb_ds/tree_policy.hpp>

#define pb push_back
#define mp make_pair

#define all(x) (x).begin(), (x).end()
#define debug(x) cerr << #x << " = " << x << '\n';

#define fi first
#define se second

using namespace std;
using namespace __gnu_pbds;

typedef long long ll;   
template<typename T> using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;

const int MAXN = (int)1e5 + 5;
const ll INF = (ll)1e15;

ll dp[MAXN][2][105], dp2[MAXN][2][105];

vector<int> adj[MAXN];

ll neigh[MAXN];

int arr[MAXN];

int n, lim;

ll ans;

void upd(ll &a, ll b) {
    if (b > a) {
        a = b;
    }
}

void dfs(int v, int pr = -1) {
    for (int i = 0; i <= lim; ++i) {
        dp2[v][0][i] = 0;
        
        if (i > 0) {
            dp2[v][1][i] = neigh[v];
        }
        else {
            dp2[v][1][i] = -INF;
        }
    }

    for (int to : adj[v]) {
        if (to != pr) {
            dfs(to, v);
            
            for (int k = 0; k <= lim; ++k) {
                upd(dp2[v][0][k], max(dp2[to][1][k], dp2[to][0][k]));
                upd(dp2[v][1][k + 1], max(dp2[to][0][k], dp2[to][1][k]) + neigh[v] - arr[to]);
            }
        }
    }
    
    for (int step = 0; step < 2; ++step) {
        for (int i = 0; i <= lim; ++i) {
            dp[v][0][i] = 0;
            
            if (i > 0) {
                dp[v][1][i] = neigh[v];
            }
            else {
                dp[v][1][i] = -INF;
            }
        }
        
        for (int to : adj[v]) {
            if (to != pr) {
                for (int a = 0; a <= lim; ++a) {
                    int b = lim - a;
                    upd(ans, dp[v][0][a] + dp2[to][1][b]);
                    upd(ans, dp[v][0][a] + dp2[to][0][b]);
                    upd(ans, dp[v][1][a] + dp2[to][1][b] - arr[to]);
                    upd(ans, dp[v][1][a] + dp2[to][0][b] - arr[to]);
                }
                
                for (int k = 0; k <= lim; ++k) {
                    upd(dp[v][0][k], max(dp[to][1][k] - arr[v], dp[to][0][k]));
                    upd(dp[v][1][k + 1], max(dp[to][0][k], dp[to][1][k] - arr[v]) + neigh[v]);
                }
            }
        }
        
        reverse(all(adj[v]));
    }
}

void solve() {
    scanf("%d %d", &n, &lim);
    
    for (int i = 1; i <= n; ++i) {
        scanf("%d", &arr[i]);
    }
    
    for (int i = 1; i < n; ++i) {
        int u, v;
        scanf("%d %d", &u, &v);
        adj[u].pb(v);
        adj[v].pb(u);
        neigh[u] += arr[v];
        neigh[v] += arr[u];
    }
    
    dfs(1);
    
    for (int i = 1; i <= n; ++i) {
        for (int s = 0; s < 2; ++s) {
            upd(ans, dp[i][s][lim]);
            upd(ans, dp2[i][s][lim]);
        }
    }
    
    printf("%lld\n", ans);
}

int main() {
    int tt = 1;

    while (tt--) {
        solve();
    }

    return 0;
}

Compilation message (stderr)

chase.cpp: In function 'void solve()':
chase.cpp:104:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d %d", &n, &lim);
     ~~~~~^~~~~~~~~~~~~~~~~~~
chase.cpp:107:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d", &arr[i]);
         ~~~~~^~~~~~~~~~~~~~~
chase.cpp:112:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d %d", &u, &v);
         ~~~~~^~~~~~~~~~~~~~~~~

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