Submission #1248915

#	Time	Username	Problem	Language	Result	Execution time	Memory
1248915		cpdreamer	Magic Tree (CEOI19_magictree)	C++20	11 / 100	104 ms	17732 KiB

magictree

#include <wchar.h>
#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
#define V vector
#define pb push_back
#define all(v) v.begin(),v.end()
const long long MOD=1e9+7;
#define P pair
void file() {
    freopen("input.txt","r",stdin);
    freopen("output.txt","w",stdout);
}
V<int>adj[(int)1e5+1];
int d[(int)1e5+1];
ll v[(int)1e5+1];
int dep[(int)1e5+1];
int l[(int)1e5+1],r[(int)1e5+1];
ll dp[(int)1e5+1];
struct segtree {
private:
    struct node {
        ll val;
    };
    node neutral={0LL};
    node single( ll v) {
        return {v};
    }
    node merge(node a,node b) {
        return {max(a.val,b.val)};
    }
public:
    int size;
    V<node>query;
    void init(int n) {
        size=1;
        while (size<n)size*=2;
        query.assign(2*size,neutral);
    }
    void set(int i,ll v,int x,int lx,int rx) {
        if (rx-lx==1) {
            query[x]=single(v);
            return;
        }
        int m=(lx+rx)/2;
        if (i<m) {
            set(i,v,2*x+1,lx,m);
        }
        else
            set(i,v,2*x+2,m,rx);
        query[x]=merge(query[2*x+1],query[2*x+2]);
    }
    void set(int i,int v) {
        set(i,v,0,0,size);
    }
    node calc(int l,int r,int x,int lx,int rx) {
        if (lx>=r || rx<=l) {
            return neutral;
        }
        if (l<=lx && rx<=r) {
            return query[x];
        }
        int m=(lx+rx)/2;
        node a=calc(l,r,2*x+1,lx,m);
        node b=calc(l,r,2*x+2,m,rx);
        return merge(a,b);
    }
    ll calc(int l,int r) {
        return calc(l,r,0,0,size).val;
    }
};

int cnt=0;

void dfs(int n,int p) {
    l[n]=cnt;
    for (auto u:adj[n]) {
        if (u==p)continue;
        cnt++;
        dep[u]=dep[n]+1;
        dfs(u,n);
    }
    r[n]=cnt;
}
bool cus(int a,int b) {
    bool f1=(l[a]>=l[b] && l[a]<=r[b]);
    bool f2=(l[b]>=l[a] && l[b]<=r[a]);
    if (f2)return true;
    if (f1)return false;
    return d[a]>d[b];
}
void solve() {
    int n,m,k;
    cin>>n>>m>>k;
    for (int i=2;i<=n;i++) {
        int a;
        cin>>a;
        adj[a].pb(i);
        adj[i].pb(a);
    }
    for (int i=1;i<=n;i++) {
        d[i]=k+1;
    }
    for (int i=0;i<m;i++) {
        int u,day;
        ll w;
        cin>>u>>day>>w;
        d[u]=day;
        v[u]=w;
    }
    int a[n];
    for (int i=0;i<n;i++) {
        a[i]=i+1;
    }
    dfs(1,-1);
    sort(a,a+n,cus);
    ll ans=0;
    for (int i=0;i<=k;i++) {
        dp[i]=0;
    }
    segtree tree;
    tree.init(k+1);
    for (auto u:a) {
        if (d[u]>k)continue;
        ll x=tree.calc(d[u],k+1)+v[u];
        ans=max(ans,x);
        if (x>dp[d[u]]) {
            dp[d[u]]=x;
            tree.set(d[u],x);
        }
    }
    cout<<ans<<endl;

}
int main(){
    //file();
    solve();

}

Compilation message (stderr)

magictree.cpp: In function 'void file()':
magictree.cpp:11:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   11 |     freopen("input.txt","r",stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
magictree.cpp:12:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   12 |     freopen("output.txt","w",stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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