Submission #1090245

#	Time	Username	Problem	Language	Result	Execution time	Memory
1090245		pmqwerty	Magic Tree (CEOI19_magictree)	C++17	3 / 100	79 ms	7804 KiB

magictree

#include<bits/stdc++.h>
using namespace std;
const int MAXN = 1e5 + 100;
vector<int> a[MAXN];
int v[MAXN];
int w[MAXN];
int d[MAXN];
int n, m, k;
int par[MAXN];
int outdegree[MAXN];
namespace sub1{
    bool check(){
        if (!(n <= 20 && k <= 20)) return 0;
        for (int i = 1; i <= m; i++){
             if (w[i] > 1) return 0;
        }
        return 1;
    }
    int mark[21];
    bool flag = true;
    void dfs(int u, int t){
        if (mark[u]){
            if (d[u] > t){
                flag = false;
            }
        }
        for (int v: a[u]){
             dfs(v, (mark[u] ? d[u]: t));
        }
    }
    void solve(){
        long long ans = 0;
        for (int mask = 0; mask < (1 << m); mask++){
             memset(mark, 0, sizeof(mark));
             long long cnt = 0;
             for (int i = 0; i < m; i++){
                  if (mask & (1 << i)){
                      mark[v[i + 1]] = true;
                      cnt += w[i + 1];
                  }
             }
             flag = true;
             dfs(1, 1e9);
             if (flag){
                 ans = max(ans, cnt);
             }
        }
        cout << ans << '\n';
    }
}
namespace sub2{
    bool check(){
        for (int i = 1; i <= m; i++){
             if (outdegree[v[i]] != 0) return 0;
        }
        return 1;
    }
    void solve(){
        long long ans = 0;
        for (int i = 1; i <= m; i++){
             ans += w[i];
        }
        cout << ans << '\n';
    }
}
bool sub3_flag = true;
namespace sub3{
    bool check(){
        if (!sub3_flag) return false;
        for (int i = 1; i <= m; i++){
             if (w[i] > 1) return false;
        }
        return true;
    }
    int lis(vector<int> const& a) {
        int n = a.size();
        const int INF = 1e9;
        vector<int> d(n+1, INF);
        d[0] = -INF;
        for (int i = 0; i < n; i++) {
            int l = upper_bound(d.begin(), d.end(), a[i]) - d.begin();
            if (d[l-1] < a[i] && a[i] < d[l])
                d[l] = a[i];
        }

        int ans = 0;
        for (int l = 0; l <= n; l++) {
            if (d[l] < INF)
                ans = l;
        }
        return ans;
    }
    void solve(){
        vector<int> temp;
        for (int i = 1; i <= m; i++){
             temp.push_back(d[i]);
        }
        cout << lis(temp) << '\n';
    }
}
int main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cin >> n >> m >> k;
    for (int i = 2; i <= n; i++){
         int x;
         cin >> x;
         a[x].push_back(i);
         outdegree[x]++;
         sub3_flag &= (x == i - 1);
    }
    for (int i = 1; i <= m; i++){
         cin >> v[i] >> d[i] >> w[i];
    }
    if (sub1::check()) sub1::solve();
    else if (sub2::check()) sub2::solve();
    else if (sub3::check()) sub3::solve();
}

• Subtask 1: 0 / 6
• Subtask 2: 3 / 3
• Subtask 3: 0 / 11
• Subtask 4: 0 / 12
• Subtask 5: 0 / 16
• Subtask 6: 0 / 13
• Subtask 7: 0 / 22
• Subtask 8: 0 / 17