Submission #1027093

#	Time	Username	Problem	Language	Result	Execution time	Memory
1027093		ShaShi	Chase (CEOI17_chase)	C++17	100 / 100	432 ms	365012 KiB

chase

#include <bits/stdc++.h>
 
#define int long long
 
// #pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
// #pragma GCC optimize("O3")
// #pragma GCC optimize("unroll-loops")
 
#define F first
#define S second
#define mp make_pair
#define pb push_back
#define all(x) x.begin(), x.end()
#define kill(x) cout << x << "\n", exit(0)
#define pii pair<int, int>
#define endl "\n"
 
 
 
 
using namespace std;
typedef long long ll;
typedef long double ld;
 
 
const int MAXN = (int)1e5 + 7;
const int MOD = (int)1e9 + 7;
const int INF = (int)1e9 + 7;
const int SQ = 107;
 
 
 
int n, m, t, k, tmp, tmp2, tmp3, tmp4, flag, u, v, w, ans;
int arr[MAXN], dp[MAXN][SQ], dp2[MAXN][SQ], sum[MAXN];
int ps[SQ][2][MAXN], pd[MAXN][SQ];
vector<int> adj[MAXN], vec[MAXN];
 
 
 
 
void DFSsz(int v, int p=-1) {
    sum[v] = 0; vec[v].clear();
 
    for (int u:adj[v]) {
        if (u == p) continue;
 
        DFSsz(u, v);
 
        sum[v] += arr[u]; vec[v].pb(u);
    }
 
    for (int j=1; j<=k; j++) {
        for (int u:vec[v]) {
            dp[v][j] = max({dp[v][j], max(dp[u][j], dp2[u][j])});
            dp2[v][j] = max({dp2[v][j], max(dp[u][j-1], dp2[u][j-1])+sum[v]});
        }
    }
 
    for (int j=1; j<=k; j++) {
        ps[j][0][0] = ps[j][1][vec[v].size()+1] = 0;
 
        for (int i=1; i<=vec[v].size(); i++) {
            int u = vec[v][i-1];
 
            ps[j][0][i] = max(ps[j][0][i-1], max(dp[u][j], dp2[u][j]));
        }
 
        for (int i=vec[v].size(); i>=1; i--) {
            int u = vec[v][i-1];
 
            ps[j][1][i] = max(ps[j][1][i+1], max(dp[u][j], dp2[u][j]));
        }
 
        for (int i=1; i<=vec[v].size(); i++) pd[vec[v][i-1]][j] = max(ps[j][0][i-1], ps[j][1][i+1]);
    }
}
 
 
 
void Walk(int v, int p, vector<int> mul) {
    for (int j=1; j<=k; j++) ans = max({ans, dp[v][j], dp2[v][j]+arr[p], mul[j], mul[j-1]+sum[v]+arr[p]});
 
    for (int u:adj[v]) {
        if (u == p) continue;
 
        vector<int> mul2(k+1);
        for (int j=1; j<=k; j++) mul2[j] = max({pd[u][j], mul[j], max(pd[u][j-1], mul[j-1])+sum[v]-arr[u]+arr[p]});
        
        Walk(u, v, mul2);
    }
}
 
 
int32_t main() {
    #ifdef LOCAL
    freopen("inp.in", "r", stdin);
    freopen("res.out", "w", stdout);
    #else
    ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    #endif
 
 
    cin >> n >> k;
 
    for (int i=1; i<=n; i++) cin >> arr[i];
 
    for (int i=1; i<n; i++) {
        cin >> u >> v;
 
        adj[u].pb(v); adj[v].pb(u);
    }
 
    DFSsz(1);
    Walk(1, 0, vector<int>(k+1, -INF));
 
 
    cout << ans << endl;
 
 
    return 0;
}

Compilation message (stderr)

chase.cpp: In function 'void DFSsz(long long int, long long int)':
chase.cpp:62:24: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   62 |         for (int i=1; i<=vec[v].size(); i++) {
      |                       ~^~~~~~~~~~~~~~~
chase.cpp:74:24: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   74 |         for (int i=1; i<=vec[v].size(); i++) pd[vec[v][i-1]][j] = max(ps[j][0][i-1], ps[j][1][i+1]);
      |                       ~^~~~~~~~~~~~~~~

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